. y t i v i t c a n a m u h m o r f g n i s i r a e s o h t e r a s r o t c a f c i n e g o p o r h t n A . e l b a l i a v a a e r a e h t o t e v i t a l e r n o i t a l u p o p e h t f o e z i s e h t o t d e t a l e r e r a s t c e f f e e h t : t n e d n e p e d y t i s n e d y l l a u s u e r a s r o t c a f c i t o i B m s i l a u t u M m s i t i s a r a p n o i t a d e r P g n i z a r G n o i t i t e p m o C : s r o t c a f c i t o i B
t a t i b a h a n i s r o t c a f c i t o i B 5 f o 2 1 of 53
Abiotic factors in a habitat Abiotic Factors: - solar energy input - Climate - Topography (altitude, slope etc) - Oxygen availability - Edaphic (factors that are connected with soil) - Pollution - Catastrophes
. e g n a h c t a t i b a h e h t n i s n o i t i d n o c e h t s s e l n u e g n a h c t o n s e o d n e t f o s i h t . d e h c a e r n e e b s a h y t i n u m m o c x a m i l c a . s e e r t y b d e t a n i m o d y l l a u s u s i t a t i b a h d n e e h t . y t i n u m m o c g n i t s i x e e h t e c a l p e r d n a n i w d n a t n e s e r p y d a e r l a s t n a l p e h t h t i w e t e p m o c y e h t . r a e p p a s t n a l p r e l l a t d n a r e g r a l m o r f s d e e s r e t t e b t e g s n o i t i d n o c e h t s a . w o r g s t n a l p d e t o o r w o l l a h s s t e l l i o s f o t n e m p o l e v e d e h t . r e t a w d l o h n e h t n a c h c i h w , l i o s e h t n i r e t t a m c i n a g r o e r o m p u s d l i u b s s o m e h t -
s e u n i t n o c n o i s s e c c u S 5 f o 4 3 of 53
Primary succession and its pionerr phase - starts in newly formed habitats where there has not been a community before. - it can occur on bare rock, sand, and open water. - Succession usually continues until a stable community is formed. Pioneer phase: - first organisms to colonise bare rock are algae. - they start to break up the rock surface, making the beginnings of soil. - They change the conditions in the habitat making them suitable for other species to colonise. - wind-blown moss spores start to grow.
. s d n u o p m o c c i n a g r o n i m o r f s d n u o p m o c c i n a g r o n w o r i e h t e k a m n a c t a h t s m s i n a g r o : ) s h p o r t o t u a r o ( s e c u d o r P
m e t s y s o c e n a n i s e l u c e l o m c i n a g r o o t n i d e t a r o p r o c n i s i y g r e n e h c i h w n i e t a r e h T : y t i v i t c u d o r p y r a m i r p
y t i v i t c u d o r p d n a s r e c u d o r P 5 f o 6 5 of 53
Secondary succession and Deflected succession Secondary succession: - Happens on bare soil where an existing community has been cleared. - plants, animals and wind bring seeds to the soil. - pioneer species that start the new community usually have the adaptations of: - seeds can be dispersed by wind. - rapid growth - short life cycle - abundant seed production Deflected succession: Is a community that remains stable because human activity prevents it from changing any further.
. d e t a c i l p e r s i e c n e u q e s A N D e h t d e d d a e r a s e d i t o e l c u n h c a t t a s e s a r e m y l o p A N D ) s e e r g e d 0 7 t a ( . e c n e u q e s d e t a e p e r R T S e h t f o t r a t s e h t t a h c a t t a s r e m i r p ) s e e r g e d 5 5 t a ( . s d n a r t s o w t o t n i s t i l p s A N D e h t ) s e e r g e d 5 9 t a ( . d e d d a e r a s e d i t o e l c u n d n a s r e k r a m t n e c s e r o u l f h t i w s r e m i r p A N D , e s a r e m y l o p A N D . s l l e c m o r f A N D e h t e s a e l e r o t t n e g r e t e d o t d e d d a s i A N D f o e l p m a s A : 1 e l c y C . A N D y p o c o t d e s u s i n o i t c a e r n i a h c e s a r e m y l o P
n o i t c a e r n i a h c e s a r e m y l o P 5 f o 8 7 of 53
DNA profiling Non coding blocks in DNA are called introns, and the coding regions are called exons. In introns DNA sequences are repeated many times, this is called short tandem repeats (STR's). A DNA profile is produced using gel electrophoresis, In which DNA fragments produced by restriction enzymes can be separated according to their size. - A single band shows when a persons maternal and paternal chromosomes have the same number of repeat units. - two bands occur when the two chromosomes have a different number of repeats at a locus. ( a locus is a place where the same STR's occur.)
. t n u o c c a o t n i n e k a t e b o t d e e n s r o t c a f e s e h T . r i a n a h t t a e h f o r o t c u d n o c r e t t e b a s i r e t a w s a , y l k c i u q e r o m l o o c l l i w t i r e t a w n i s i y d o b e h t f I s g n i d n u o r r u s f o e r u t a r e p m e t y t i d i m u h t n e m e v o m r i a g n i h t o l c n o i t i s o p y d o b e z i s y d o b : s s e c o r p s i h t t c e f f a l l i w t a h t s r o t c a f y n a m e r a e r e h t , h t a e d r e t f a n o o s s l o o c y d o b e h t s a d e s u e b n a c e r u t a r e p m e t y d o B
h t a e d f o e m i t e h t g n i g n i m r e t e D 5 f o 0 1 9 of 53
DNA profiling continued How a DNA profile is made using gel electrophoresis: - double-stranded DNA is added to a restriction enzyme which cuts the DNA into fragments. - fragments of double-stranded DNA are loaded into the wells of an agarose gel in a tank using micropipette. - the negatively charged DNA moves towards the positive electrode. The fragments separate into the invisible bands. - DNA is transferred to a nylon or nitrocellulose membrane by solution drawn up through the gel. DNA double strands split and stick to the membrane. - Membrane placed in a bag with DNA probe. Single-stranded DNA probe binds to fragments with a complimentary sequence. - if DNA is radioactive x-ray film is used to detect fragments, if fluorescent it is seen using UV light.
. d e r u t a n e d e m o c e b s e m y z n e e h t s a s e e r g e d 8 3 - 1 2 s i n o i t i s o p m o c e d r o f t s e b e r u t a r e p m e t . s e t a l f e d y d o b e h t d n a d e s a e l e r s i s a g e h t s e u n i t n o c n o i t i s o p m o c e d s a ) k e e w a r e t f a ( . g n i t a o l b g n i s u a c s e n i t s e t n i e h t i m r o f n e g o r d y h d n a a i n o m m a , e d i x o i d n o b r a c , e n a h t e m , e d i h p l u s n e g o r d y h g n i d u l c n i s e s a g a i r e t c a b f o n o i t c a e h t o t e u d . n i k s e h t n o r a e p p a n a c s r e t s i l b d i u q i l r o s a g . k c a l b - e l p r u p o t n e h t n e e r g - h s i d d e r o t s n e k r a d t I . y d o b e h t f o t s e r e h t s s o r c a s d a e r p s t i ) h t a e d r e t f a s r u o h 2 7 - 6 3 ( . n i b o l g o m e a h p l u s f o n o i t a m r o f a o t e u d , n e m o d b a r e w o l e h t f o n i k s e h t f o n o i t a r o l o c s i d h s i n e e r g a s i n g i s t s r i F -
) n o i t a c a f e r t u p r o ( n o i t i s o p m o c e D 5 f o 2 1 11 of 53
Rigor mortis After death the muscles relax then suddenly stiffen, this is known as rigor mortis. The steps at which this occurs are: - cells become starved of oxygen, oxygen dependent reactions stop. - respiration in the cells becomes anaerobic and produces lactic acid. - the pH of the cells fall, inhibiting enzymes and then inhibiting anaerobic respiration. - the ATP needed for muscle contraction is not produced, bonds between muscle proteins become fixed. - the proteins can no longer move over one another to shorten the muscle. - this fixes the muscles and joints. This usually happens 6-9 hours after death.
s e c a f r u s o t h c a t t a o t a i r e t c a b w o l l a t a h t s e b u t n i e t o r p = s u l i p A N D f o s e l c r i c l l a m s = s d i m s a l p A N D r a l u c r i c n i a m n o i t a r i p s e r f o e t i s , e n a r b m e m e c a f r u s l l e c e h t f o g n i d l o f - n i = e m o s o s e m t n e m e v o m l l e c r o f d e s u = m u l l e g a l f n o i t c e t o r p r o f r e y a l s u c u m a = e l u s p a c s i s e h t n y s n i e t o r p f o e t i s = s e m o s o b i r e n a r b m e m e c a f r u s l l e c l l a w l l e c : m o r f e d a m s i m u i r e t c a b A . n o i s s i f y r a n i b y b y l l a u x e s a e c u d o r p y e h T . s g n i h t r e h t o g n o m a s u e l c u n a e v a h t o n o d y e h t s n a e m h c i h w c i t o y r a k o r p e r a a i r e t c a b
a i r e t c a B 5 f o 4 1 13 of 53
Forensic entomology - A persons time of death can also be estimated by using entomology. - The rate of maggot development can be used as they accumulate on the body shortly after death. - its stage of development can tell us its age. - usually blowflies will lay eggs within one day of finding the body. - some factors can increase the maggots development such as cocaine. Succession on corpses: - as each organism feeds on a body it changes it - this change makes it more attractive to other species of organism which changes the body for the next group - until the body is reduced to a skeleton
d l i h c o t r e h t o m m o r f n o i s s i m s n a r t l a n r e t a m r e f s n a r t d o o l b o t d o o l b t c e r i d x e s d e t c e t o r p n u s e l d e e n g n i r a h s : y b d e t t i m s n a r t e b n a c V I H
g n i z e e n s r o g n i h g u o c e l p o e p y b d e s u a c s i s i h t s u c u m f o s t e l p o r d n i r i a e h t h g u o r h t d e i r r a c s i : y b d e t t i m s n a r t e b n a c B T
B T d n a V I H f o n o i s s i m s n a r T 5 f o 6 1 15 of 53
Viruses Consist of: - a strand of DNA or RNA (Viral DNA can be single or double stranded.) - protein coat How viruses reproduce: - virus attaches to a hosts cell - virus inserts nucleic acid - the viral DNA replicates - viral protien coats are made - new virus particles are formed - virus particles are released
g n i y l p i t l u m m o r f s e s u r i v s t n e v e r p : n o r e f r e t n I s e b o r c i m e h t y o r t s e d n e h t h c i h w s e g a h p o r c a m d n a s e t y c o h p m y l e t a v i t c a t n e s e r p s n e g o h t a p y n a s e d o n h p m y l e h t h g u o r h t s e s s a p h p m y l s a s l e s s e v h p m y l g n o l a s w o l f d i u l f h p m y l e h t s l e s s e v c i t a h p m y l o t n i s n i a r d d i u l f e u s s i t : s e d o n h p m y l . l a i r e t a m n g i e r o f e h t y o r t s e d t a h t s e m y z n e g n i s a e l e r e l o u c a v h t i w e s u f s e m o s o s y l e l o u c a v n i d e s o l c n e e g a h p o r c a m r o l i p o r t u e n y b d e f l u g n e e c a f r u s n o s n e g i t n a h t i w m u i r e t c a b : a i r e t c a b f o g n i f l u g n E
d e u n i t n o c n o i t c e f n i o t s e s n o p s e r c i f i c e p s - n o N 5 f o 8 1 17 of 53
Non-specific responses to infection Lysozyme: - an enzyme that breaks down the cell walls of bacteria, found in tears and saliva. Inflammation: - when a cut lets microbes enter the body the inflammatory response destroys them. - White blood cells release chemicals such as histamine which cause the arterioles to dilate increasing blood flow to the site. Phagocytosis: - are white blood cells that engulf bacteria - neutrophils - lymphocytes (B cells and T cells) - monocytes (become macrophages) - and other white cells which produce histamine
. ' f l e s n o n ' s a d e l e b a l n e e b e v a h t a h t e c a f r u s e h t n o s n e g i t n a h t i w s l l e c y n a y o r t s e d = s l l e c r e l l i k T . s e t y c o g a h p f o y t i v i t c a e h t e c n a h n e o s l a . s e i d o b i t n a g n i c u d o r p f o e l b a p a c s l l e c e m o c e b d n a e d i v i d o t s l l e c B e t a l u m i t s = s l l e c r e p l e h T . e p a h s y r a t n e m i l p m o c e h t h t i w s n e g i t n a o t d n i b h c i h w s r o t p e c e r n e g i t n a c i f i c e p s e v a h y e h t . w o r r a m e n o b e h t n i d e c u d o r p e r a : s e t y c o h p m y l T
d e u n i t n o c y t i n u m m i c i f i c e p s 5 f o 0 2 19 of 53
specific immunity B lymphocytes: - secrete antibodies in response to antigens - special protein molecules of a class known as immunoglobulins - B cell produces antibodies which which bind to bacteria with antigens on surface this labels them as 'non self' - antibody binds to antibody receptor on a macrophage - macrophage engulfs antibodies and bacterium - lysosomes fuse with vacuole releasing enzymes which destroy the bacteria.
. n o i t c u r t s e d o f m e h t g n i y f i t n e d i s n e g i t n a o t d n i b h c i h w s e i d o b i t n a e t e r c e s s l l e c a m s a l p s l l e c a m s a l p o t n i e t a i t n e r e f f i d s l l e c r o t c e f f e B s l l e c r o t c e f f e B d n a s l l e c y r o m e m B e v i g o t s e d i v i d l l e c B e h t . l l e c B e t a l u m i t s t a h t ) s n i e t o r p ( s e n i k o t y c s e c u d o r p d n a C P A o t s d n i b r o t p e c e r y r a t n e m i l p m o c h t i w l l e c r e p l e h T d e t a v i t c a ) C P A ( l l e c g n i t n e s e r p - n e g i t n a n a s e m o c e b l l e c B r o t p e c e r y r a t n e m i l p m o c h t i w l l e c B o t s d n i b n e g i t n a e c a f r u s n o s n e g i t n a h t i w m u i r e t c a b -
n o i t c e l e s l a n o l C 5 f o 2 2 21 of 53
Activation of T helper cells - bacterium with antigens on surface - bacterium engulfed by macrophage - macrophage presents antigens on its surface and becomes an antigen presenting cell (APC) - APC binds to T helper cell with complimentary CD4 receptors - the T helper cell is activated and divides - clone of T memory cells and clone of active T helper cells are produced
e u g i t a f e m e r t x e d n a r e v e f s s o l t h g i e w d n a e t i t e p p a f o s s o l h t a e r b f o s s e n t r o h s ) d o o l b p u h g u o c n e v e n a c ( g n i h g u o c : B T f o s m o t p m y S s l l e c T r e l l i k y b k c a t t a d n a n o i t c u d o r p y d o b i t n a s e c u d e r s i h t s l l e c T s s e r p p u s n a c a i r e t c a b B T d e t a v i t c a e r a y e h t d n a s n e k a e w m e t s y s e n u m m i e h t l i t n u t n a m r o d e i l n a c y e h t n w o d k a e r b o t d r a h m e h t g n i k a m s l l a w y x a w k n i h t e v a h y e h t s e g a h p o r c a m e h t e d i s n i e v i v r u s n a c a i r e t c a b B T -
B T f o n o i t c e f n I 5 f o 4 2 23 of 53
The role of T killer cells - Bacterium infects cell of host - the cell presents the antigens and becomes an APC - T killer cell with complimentary receptor binds to the APC - the T killer cell divides to form two clones active T killer cells and memory T killer cells. Cytokines from T helper cells stimulate the differentiation. - The active T killer cells bind to infected cells presenting antigens. - T killer cell releases chemicals that cause pores to form in the infected cell causing it to explode. - The infected cell dies.
. d e r s a p u w o h s s a e r a d e g a m a d , B T h t i w n o s r e p a n i s g n u l e h t n i e g a m a d f o t n e t x e e h t e e s o t d e s u e b n a c s y a r - x : s y a r - x t s e h C a i r e t c a b e h t y f i t n e d i o t d e s u n e h t e r a s n i a t s t n e s e r p e r a a i r e t c a b t a h w e e s o t d e r u t l u c n e h t s i t i n e k a t s i t n e i t a p a y b p u d e h g u o c m u t u p s f o e l p m a s a : a i r e t c a b f o n o i t a c i f i t n e d I t n e s e r p y d a e r l a s n e g i t n a B T g n i w o h s n o i t a m m a l f n i s i h t e s u a c d o o l b e h t n i s e i d o b i t n a a e r a d e m a l f n i s w o h s t l u s e r e v i t i s o p n i k s r e d n u d e t c e j n i s i n i l u c r e b u t f o t n u o m a l l a m s : s t s e t d o o l b d n a n i k S
? d e s o n g a i d B T s i w o H 5 f o 6 2 25 of 53
The role of fever A person infected with TB can get a fever. This is caused by: - as part of the inflammatory response fever causing substances are released from neutrophils and macrophages - these chemicals affect the hypothalamus and alter the set point for the core body temperature to a higher temperature -effectors act to warm up the body to the new set point - a raised temperature enhances immune function and phagocytosis - bacteria and viruses may reproduce slower at higher temperatures - although a high temperature can be harmful to the patient as it denatures enzymes
e s a r g r e t n i g n i s u e m o n e g s ' l l e c t o h e h t o t n i d e t a r g e t n i n e h t s i t i e m o n e g n a m u h e h t o t n i d e t r e s n i e b n a c t a h t d n a r t s e l b u o d a e k a m o t d e i p o c s i A N D e h t A N R e h t f o y p o c A N D a s e k a m t i e s a t p i r c s n a r t e s r e v e r d e l l a c e m y z n e n a s e s u : s e t a c i l p e r s u r i v e h t w o H o o t m e h t t c e f n i n a c s u r i v e h t o s s r o t p e c e r 4 D C e v a h o s l a s e g a h p o r c a m l l e c e h t s r e t n e n e h t A N R l a r i v e h t e n a r b m e m l l e c r e p l e h T e h t h t i w e s u f o t e p o l e v n e e h t g n i w o l l a r o t p e c e r d n o c e s a h t i w e n i b m o c n e h t y e h t s l l e c r e p l e h T f o e c a f r u s e h t n o s r o t p e c e r 4 D C e h t o t d n i b 0 2 1 p g : m e t s y s e n u m m i e h t n i h t i w s l l e c r e p l e h I s e d a v n i V I H
s l l e c r e p l e h T s e d a v n i V I H 5 f o 8 2 27 of 53
HIV and AIDS AIDS is caused by infection with the human immunodeficiency virus HIV.
s y a w t n e r e f f i d n i d e c i l p s s i t i f i A N R m f o h t g n e l e n o m o r f d e m r o f e b n a c s n i e t o r p l a r e v e s s n a e m t a h t s n o x e d e l l a c e r a s n o i g e r g n i d o c e r a h c i h w s e c n e u q e s g n i n i a m e r e h t d e v o m e r e r a s n o r t n i g n i d o c - n o n e h t d e t i d e n e t f o s i A N R -
g n i c i l p s A N R m 5 f o 0 3 29 of 53
Transcription and Translation Transcription: - RNA polymerase attaches to the DNA - hydrogen between the paired bases break and the DNA unwinds - RNA nucleotides with complimentary bases to the ones on the template strand bond together forming mRNA - mRNA then leaves the nucleus through a pore in the nuclear envelope Translation: - mRNA attaches to a ribosome -the anticodons on tRNA are complimentary to the mRNA codons for the amino acid - free amino acids attach to the correct tRNA molecule which carry it to the ribosome - the anticodons bind to the codons and form a chain of amino acids which are held together with a peptide bond
s e s a e s i d r e h t o o t e l b a r e n l u v m e t s y s e n u m m i e h t e v a e l n a c d n a S D I A f o t e s n o e h t s e t a c i d n i s l l e c r e p l e h T f o r e b m u n w o l d n a n o i t a l u c r i c n i s e s u r i v f o r e b m u n d e s a e r c n i e h t : e s a h p e s a e s i d e h T e t a v i t c a e r n a c s e s a e s i d t n a m r o d r u c c o n a c s m o t p m y s e r o m d n a s n e k a e w m e t s y s e n u m m i : e s a h p c i n o r h c e h T n o i t a c i l p e r s u r i v f o e t a r e h t s e c u d e r y l t a e r g s i h t m e h t y o r t s e d o t t r a t s h c i h w s l l e c r e l l i k T y b d e s i n g o c e r e r a s l l e c r e p l e h T d e t c e f n i s k e e w w e f a r e t f a s l l e c r e p l e h T f o s s o l d n a s u r i v e h t f o n o i t a c i l p e r d i p a r a s i e r e h t s m o t p m y s o n e v a h r o s m o t p m y s t e g r e h t i e o t s t r a t s n o s r e p d e t c e f n i e h t s k e e w 2 1 - 3 r e t f a d o o l b e h t n i r a e p p a s e i d o b i t n a V I H : e s a h p e t u c a e h t
S D I A - e s a e s i d e h t f o e s r u o c e h T 5 f o 2 3 31 of 53
How HIV destroys T helper cells - HIV binds to cell receptors virus envelope fuses with cell surface membrane - virus reverse transcription copies viral RNA into viral DNA - intergrase inserts viral DNA into host DNA - transcription occurs - translation of virus envelope proteins - virus envelope proteins are incorporated into the cell membrane - the virus mRNA is translated - virus particle budding becomes wrapped in cell membrane, forming the virus protein
s n e g o h t a p t s n i a g a e s n e f e d e h t n i l u f e s u e r a h c i h w d i c a c i t c a l e k i l s l a c i m e h c e t e r c e s y e h t s a s s e c o r p e v i t s e g i d e h t n i d i a n a c a i r e t c a b e h t l a e d i e r a s n o i t i d n o c e r e h w t u g e h t n i h t i w g n i v i l m o r f t i f e n e b a r o l f l a r u t a n s e n i t s e t n i e g r a l d n a l l a m s e h t n i d n u o f e r a a i r e t c a b : a r o l f t u G d o o f h t i w r e t n e t a h t a i r e t c a b t s o m s l l i k s i h t 0 . 2 n a h t s s e l f o H p a g n i v i g d i c a c i r o l h c o r d y h n i a t n o c l l i w s l l a w h c a m o t s e h t n i s d n a l g c i r t s a g y b d e t e r c e s s e c i u j c i r t s a g : d i c a h c a m o t s : m e t s y s e v i t s e g i d e h t n I
d e u n i t n o c s n e g o h t a p f o y r t n e g n i t n e v e r P 5 f o 4 3 33 of 53
Preventing entry of pathogens The skin: - the skins keratin (hard protein) outer layer stops entry of microorganisms - entry can occur through wounds but blood clotting stops further enrty - large numbers of microbes called skin flora live on the skin surface they prevent colonisation of other bacteria Mucous membranes: - the mucus membranes line the airways and gut and provide easier routes into the body - entry of microbes into the lungs is limited by the action of mucus and cilia - the mucus traps microbes and the cilia carry the mucus to the throat where it is swallowed - tears and saliva contain lysozyme which breaks down bacterial cell walls
. y t i n u m m i d r e h d e l l a c s i t i s n e p p a h s i h t n e h W . d e t c e t o r p o s l a s i s u r i v e h t t e g t o n d i d o h w e n o y n a t a h t s n a e m s i h T . s r e h t o o t d e r r e f s n a r t e b o t y l e k i l s s e l s i e s a e s i d e h t d e s i n u m m i e r a e l p o e p h g u o n e n e h w n e g o h t a p e h t f o t n e m g a r f g n i r a e b - n e g i t n a n a m r o f s s e l m r a h a o t n i d e r e t l a n e e b s a h t a h t n i x o t a d e l l i k n e e b s a h t a h t a i r e t c a b n i a t n o c y a m s e n i c c a v = a i r e t c a b d e l l i K s s e l m r a h e r a y e h t o s d e n e k a e w n e e b e v a h s e s u r i v e s e h t = s e s u r i v d e t a u n e t t A : g n i w o l l o f e h t n i a t n o c y a m s e n i c c a V
d e t a n i c c a v g n i e B 5 f o 6 3 35 of 53
Becoming immune You can become immune to a disease in these ways:
-active artificial immunity = being vaccinated against specific diseases, this vaccine stimulates specific immune responses which give her immunity to the disease - passive artificial immunity = when a patient who is in danger of getting a disease is given specific antibodies to stop them from getting a particular disease - active natural immunity = when a person has had a disease in the past and has made specific B memory and T memory cells to help combat the disease if the person gets it again - passive natural immunity = when a baby has just been born its immune system is undeveloped, but its mother has given it antibodies via the placenta
l l e c l a i r e t c a b e h t n i d n u o f s e m y z n e c i f i c e p s f o n o i t i b i h n i d e c u d o r p t o n e r a s n i e t o r p l a i t n e s s e t a h t g n i n a e m s i s e h t n y s n i e t o r p f o n o i t i b i h n i n o i s i v i d l l e c s t n e v e r p h c i h w n o i t p i r c s n a r t d n a n o i t a c i l p e r , s i s e h t n y s d i c a c i e l c u n f o n o i t i b i h n i y t i l i b a e m r e p n i s e g n a h c g n i s u a c e n a r b m e m l l e c e h t f o n o i t p u r s i d ) l l e c e h t f o g n i t s r u b o t d a e l n a c s i h t ( s i s e h t n y s l l a w l l e c l a i r e t c a b f o n o i t i b i h n i : n o i s i v i d d n a h t w o r g l l e c l a i r e t c a b t p u r s i d s c i t o i b i t n a w o H s n e g o h t a p e h t y o r t s e d n e h t n a c m e t s y s e n u m m i n w o s t s o h e h t , a i r e t c a b f o n o i t a c i l p i t l u m e h t t n e v e r p t a h t s c i t o i b i t n a = c i t a t s o i r e t c a b a i r e t c a b y o r t s e d t a h t s c i t o i b i t n a = l a d i c i r e t c a b : s c i t o i b i t n a f o s e p y t o w t e r a e r e h T
k r o w s c i t o i b i t n a w o H 5 f o 8 3 37 of 53
Treating AIDS and TB Treating AIDS: There are two types of drugs that reduce the the production of more viruses. - reverse transcriptase inhibitors = prevent the viral RNA from making DNA for integration into the hosts genome - protease inhibitors = inhibit the proteases that catalyse the cutting of larger proteins into small polypeptides for use in the construction of more viruses Treating TB: - active TB bacteria can be killed by antibiotics - this goes on for 6 months until all dormant bacteria are destroyed
t n a t s i s e r w o n e r a a i r e t c a b h t o b d i m s a l p e t e l p m o c a e k a m o t d n a r t s e h t s e t a c i l p e r a i r e t c a b h c a e l l e c t n a t s i s e r - n o n e h t o t d e r r e f s n a r t s i A N D d i m s a l p e h t f o d n a r t s e n o l l e c l a i r e t c a b t n a t s i s e r - n o n a s d n i f e c n a t s i s e r c i t o i b i t n a r o f e n e g a g n i y r r a c l l e c d i m s a l p l a i r e t c a b t n a t s i s e r a : ) n o i t u l o v e l a t n o z i r o h r o ( n o i t a g u j n o C . d e y o r t s e d e r a y e h t e r o f e b c i t o i b i t n a e h t o t t p a d a d n a e t a t u m o t t h g i f l l i w a i r e t c a b e h t t n e s e r p a i r e t c a b h t i w t s o h e h t o t n i d e t c e j n i s i c i t o i b i t n a n a f i o S . e v i v r u s o t r e d r o n i t n i a r t s n o c e h t o t t p a d a o t m e t s y s e h t n i h t i w s e i c e p s l l a n o e r u s s e r p t u p l l i w t i m e t s y s o c e n a n o t u p s i d n i k y n a f o t n i a r t s n o c a n e h W : e r u s s e r p n o i t c e l e S
n o i t a g u j n o C d n a s e r u s s e r p n o i t c e l e S 5 f o 0 4 39 of 53
Why do we still have diseases like TB? Bacterial populations evolve very quickly because: - bacteria reproduce very fast - bacterial population sizes are usually in billions, so the number os cells containing mutations is vast - some of these random mutations can be beneficial to the bacteria. Such mutations can make the bacteria: -use different food sources - reproduce more quickly - infect other cells more successfully
d e s a e l e r e r a e d i x o i d n o b r a c d n a y g r e n e , r e t a w e k a m o t n e g y x o h t i w s e n i b m o c n e g o r d y h e h t d n a t r a p a d e l l u p s i e s o c u l g n o i t a r i p s e r c i b o r e a n i n o i t a r i p s e r g n i r u d n e g y x o h t i w s t c a e r e t a r d y h o b r a c e h t n i d e r o t s n e g o r d y h e h t n e h w y g r e n e f o s t n u o m a e g r a l e s a e l e r o t l a i t n e t o p e h t s a h l e u f e h T : e s o c u l g e h t g n i s U e s o c u l g l e u f e t a r d y h o b r a c e h t m r o f o t d e c u d e r n e h t s i e d i x o i d n o b r a c n e g o r d y h e r o t s o t r e d r o n i e d i x o i d n o b r a c h t i w s t c a e r n e g o r d y h e h t : r e t a w m o r f n e g o r d y h g n i r o t S r e t a w f o s i s y l o t o h p s a n w o n k s i s i h t r e t a w t i l p s o t t h g i l m o r f y g r e n e s e s u s i s e h t n y s o t o h p y g r e n e s e r i u q e r n e g y x o d n a n e g o r d y h o t n i r e t a w f o g n i t t i l p s e h t : r e t a w m o r f n e g o r d y h g n i s a e l e R
s i s e h t n y s o t o h P 5 f o 2 4 41 of 53
Antibiotic resistance and hospital aquired infecti Infection control: - hand wash stations - hand wash signs - no wearing ties, watches or long sleeves Preventing the development and spread of resistant bacteria: - antibiotics should only be used when needed - patients should complete their treatment even when they feel better so that all bacteria is destroyed - infection control should be used in hospitals to prevent bacteria spreading
s i s e h t n y s o t o h p f o t c u d o r p e h t s e r o t s - n i a r g h c r a t S O 2 H d n a 2 O C o t e l b a e m r e p s i h c i h w - e n a r b m e m r e t u o h t o o m S s e l u c e l o m r e t s o p s n a r t s n i a t n o c h c i h w - e n a r b m e m r e n n i h t o o m S r e h t o n a e n o o t d e n i o j s d i o k a l y h t f o k c a t s a - m u n a r G . s i s y l o t o h p r o f s e m y z n e s n i a t n o c s c a s e n a r b m e m d i o k a l y h t e h t n i h t i w d i u l f - e c a p s d i o k a l y h T s n o i t c a e r t n e d n e p e d n i - t h g i l e h t t u o y r r a c o t d e d e e n s e m y z n e e h t l l a s n i a t n o c . s e n a r b m e m d i o k a l y h t e h t g n i d n u o r r u s d i u l f e h t - a m o r t S s n i e t o r p r i e h t f o e m o s r o f s e n e g n i a t n o c s t s a l p o r o l h c - p o o l A N D . s n o i t c a e r t n e d n e p e d - t h g i l e h t n i d e v l o v n i e r a d n a s e n a r b m e m e h t n i d e d d e b m e d n a s n i e t o r P . s c a s d e l l i f - d i u l f d e n e t t a l f d e t c e n n o c r e t n i f o m e t s y s a - e n a r b m e m d i o k a l y h T
t s a l p o r o l h c a f o e r u t c u r t S 5 f o 4 4 43 of 53
How photosynthesis works There are two main stages: Light-dependent reactions = - use energy from light and hydrogen from photolysis of water to produce reduced NADP, ATP and the waste product oxygen - the oxygen is then either used directly in respiration or released into the atmosphere Light-independent reactions = - use the reduced NADP and ATP from the light-dependent reaction to reduce carbon dioxide to carbohydrates The co-enzyme NADP is reduced when electrons are added during photosynthesis.
. s d i c a o n i m a s a h c u s s d n u o p m o c c i n a g r o r e h t o o t n i d e t r e v n o c e b n e h t n a c e s o x e h . e s o x e h d e l l a c r a g u s n o b r a c - 6 a f o n o i t a e r c e h t n i d e v l o v n i e r a d e m r o f s ' P L A G 2 1 y r e v e f o t u o o w T . n o i t c a e r e h t r o f y g r e n e e h t s e d i v o r p s n o i t c a e r t n e d n e p e d - t h g i l e h t m o r f P T A . s n o i t c a e r t n e d n e p e d - t h g i l e h t m o r f P D A N d e c u d e r e h t m o r f s e m o c n o i t c u d e r e h t r o f n e g o r d y h e h T . P L A G d e l l a c e t a h p s o h p r a g u s n o b r a c - 3 a m r o f o t d e c u d e r s i d n u o p m o c n o b r a c - 3 s i h t . P G , s e l u c e l o m n o b r a c - 3 o w t o t n i n w o d s k a e r b y l t a i d e m m i d n a e l b a t s n u s i d e m r o f d n u o p m o c n o b r a c - 6 e h T . O C S I B u R e m y z n e e h t y b d e s y l a t a c s i n o i t c a e r s i h T . P B u R d e l l a c d n u o p m o c n o b r a c - 5 a h t i w s e n i b m o c 2 O C : e l c y c n i v l a C e h t d e l l a c y a w h t a p l a c i l c y c a m r o f s n o i t c a e r e h T
) a m o r t s ( s n o i t c a e r t n e d n e p e d n i - t h g i L 5 f o 6 4 45 of 53
Light-dependent reactions (chlorophyll) - energy from the light raises two electrons to a higher energy level - the electrons leave the chlorophyll and pass along electron carriers - the electrons pass from one carrier to the next in a series of oxidation and reduction reactions losing its energy in the process - the energy is used in the synthesis in a process called photophosphorylation - the electrons lost from the chlorophyll must be replaced - within the thylakoid space an enzyme catalyses splitting of water to give oxygen gas, hydrogen ions and electrons - these electrons replace the ones lost in the chlorophyll molecule and the hydrogen ion concentration is raised as a result of photolysis - the electrons that have passed along the electron transport chain combine with NADP and hydrogen ions from the water to form reduced NADP
. s i s e h t n y s o t o h p f o e t a r e h t e c n e u l f n i o s l a l l i w s r o t c a f g n i t i m i L t n e m n o r i v n e e h t o t d e r r e f s n a r t s i d n a y g r e n e e k a m o t s s e c o r p e h t g n i r u d t s o l s i e m o s s e v a e l m o r f r e t a w g n i t a r o p a v e n i d e s u t u b l l y h p o r o l h c y b d e b r o s b a t o n y g r e n e f o % 0 5 t s a l p o r o l h c e h t n i l l y h p o r o l h c y b d e b r o s b a % 0 4 f a e l e h t h g u o r h t t h g i a r t s d e t t i m s n a r t % 5 d e t c e l f e r % 5 : f a e l t n a l p a s t i h t i n e h w t h g i l e h t o t s n e p p a h t a h W
h t h g u o r h t y g r e n e f o r e f s n a r t e h t s i t n e i c i f f e w o H 5 f o 8 4 47 of 53
Energy transfer and feeding relationships Hetrotrophs cannot make their own food instead they must consume it. Types of consumers are: - primary consumers (herbivores) are hetrotrophs that eat plat material - secondary consumers (carnivores) feed on primary consumers - tertiary consumers (carnivores) eat other consumers. the carnivores at the top of the food chain are sometimes called top carnivores. - animals that eat plants and other animals are known as omnivores - detrivores are primary consumers that feed on dead organic matter (detritus) - decomposers are species of bacteria that feed on the dead remains of animals Food chain: is the way energy is transferred in a ecosystem. The position a species occupies in a food chain is called its trophic level.
r e m m u s n i s l e s s e v w o r r a n d n a g n i r p s n i d e c u d o r p e r a s l e s s e v e d i w s l e s s e v m e l y x f o r e y a l w e n a s e c u d o r p e e r t a r a e y y r e v e : y g o l o n o r h c o r d n e D t s e b s e h s i r u o l f t i h c i h w n i s n o i t i d n o c r a l u c i t r a p s a h t n a l p f o s e i c e p s h c a e t a e p e h t r e d l o e h t r e y a l e h t r e p e e d e h t : s r e y a l n i s m r o f t a e p n e l l o p f o e p y t e u q i n u a s a h t n a l p f o s e i c e p s h c a e y a c e d o t t n a t s i s e r y r e v s i t a h t r e y a l r e t u o h g u o t a e v a h s n i a r g n e l l o p s t n u o m a t s a v n i n e l l o p e c u d o r p s t n a l p : e s u a c e b s e t a m i l c t s a p g n i t c u r t s n o c e r r o f l u f e s u s i t a e p m o r f n e l l o p
y g o l o n o r h c o r d n e d d n a s n i a r g n e l l o P 5 f o 0 5 49 of 53
Energy in a ecosystem Gross primary productivity (GPP): The rate at which energy is incorporated into organic molecules by an ecosystem. Net primary productivity (NPP): The rate at which energy is transferred into the organic molecules that make up the new plant biomass. Respiration (R): plant respiration
NPP = GPP - R
e c u d o r p e r t o n n a c t u b e g a e v i t c u d o r p e r o t e v i v r u s s d i r b y h - y t i l i r e t s d i r b y h d e e r b o t h g u o n e g n o l e v i v r u s t o n o d y e h t t u b s e c u d o r p e r a s d i r b y h s e i c e p s e m o s n i - y t i l i b a i v n i d i r b y h r o i v a h e b p i h s t r u o c s r e h t o h c a e o t d n o p s e r t o n o d t u b , a e r a e m a s e h t n i t s i x e s e i c e p s e h t - n o i t a l o s i l a r o i v a h e b s e m i t t n e r e f f i d t a e c u d o r p e r t u b a e r a e m a s e h t n i t s i x e s e i c e p s e h t - n o i t a l o s i l a r o p m e t t a t i b a h e h t f o s t r a p t n e r e f f i d y p u c c o s e i c e p s e h t - n o i t a l o s i l a c i g o l o c e
g n i d e e r b r e t n i s e i c e p s g n i t n e v e r p - n o i t a l o s I 5 f o 2 5 51 of 53
The greenhouse effect Solar radiation (visible and ultraviolet): - most ultraviolet is absorbed by ozone in the stratosphere - some visible radiation is reflected by the earth - some is reflected by clouds - most solar radiation is absorbed by the earths surface which warms it up Infrared radiation from the earth: - some infrared is absorbed by greenhouse gasses warming the troposphere - some infrared emitted by the earth's surface escapes and cools down the earth The greenhouse effect: - sun's radiation (mainly visible) passes through the glass - infrared radiation is emitted by the plants and soil, some infrared radiation is absorbed by the glass
. 2 O C s e s a e l e r h c i h w e n o t s e m i l s e d o r e n i a r d i c A . s l e v e l 2 O C e h t e s a e r c n i d l u o c n i a r d i c a d n a y t i v i t c a c i n a c l o v n i e s a e r c n i n a o s : 2 O C e s a e l e r y a m n i a r d i c a d n a s e o n a c l o V . e d i x o i d n o b r a c d e t a l u m u c c a s t i s e s a e l e r m e h t g n i n r u b t u b , r i a e h t m o r f e d i x o i d n o b r a c s e v o m e r t I . k n i s n o b r a c a d e l l a c s i s i h t , e r e h p s o m t a e h t o t n i t i g n i s a e l e r f o d a e t s n i m e h t e d i s n i e d i x o i d n o b r a c k c o l s l e u f l i s s o F : s l e u f l i s s o f f o n o i t s u b m o C . d e b r o s b a n e h t d e s a e l e r e b d l u o w e d i x o i d n o b r a c e r o m m r e t t r o h s e h t n i , p o r d d l u o w s i s e h t n y s o t o h p n w o d t u c e r e w t s e r o f a f i : n o i t a t s e r o f e D
? g n i s a e r c n i n o i t a r t n e c n o c 2 O C s i y h W 5 f o 3 5
