Biology ms flashcards

Why does anaerobic respiration produce less ATP than aerobic

oxygen is not present as the final electron carrier

no oxidative phosphorylation and most of the ATP is produced in oxidative phosphorylation

only glycolysis occurs which only produces 2 ATP

only substrate-linked phosphorylation occurs

what happens in the link reaction

Pyruvate is decarboxylated and dehydrogenated

2C acetyl group binds to co-enzyme A to produce acetyl co-enzyme A

difference between chemiosmosis in mitochondria and chlorplasts

oxidative phosphorylation in mitochondria and photophosphorylation in chloroplasts

electron transporters present in inner mitochondrial membrane while for chloroplasts it is thylakoid membrane

makes H20 for mitochondria and makes NADP+ for chloroplasts

role of NAD in aerobic conditions

acts as coenzyme

reduces pyruvate in glycolysis/redox reactions mention

releases H+ to carrier on ETC for oxidative phosphorylation

rice adaptations for anaerobic conditions

root cells able to tolerate large levels of ethanol

as they have high concentration of ethanol dehydrogenase

aerenchyma present

due to low concentration of oxygen in water ethanol produced due to anaerobic conditions

respiratory quotient

ratio volume of CO2 exhaled /volume of O2 inhaled

per unit time

importance of cristae and the inner membrane

contains the electron transport chain

has proton pumps which pump H+ into intermembrane space resulting in electrochemical gradient

contains the proteins necessary for oxidative phosphorylation

folded to allow for larger surface area

contains ATP synthase protein

why lipids produce more energy than carbs

more C-H bonds so more NAD+ is produced which results in more ATP/gram

Why ATP is so good as universal energy currency

Hydrolyses to form AMP, ADP and Pi

releases 30.5 kj/mol of energy

high turnover rate and can be regenerated

small/soluble so can move freely within cell

function of chloroplasts and their strucutre

stroma: contains enzymes like NADP and RuBP

starch grains: to allow storage of products of photosynthesis like glucose

thylakoid: light dependent reaction’s site

stroma: light independent reaction’s site

thylakoid membrane: contains ETC, photosystems and ATP synthase

chromatography use to identify pigments

spot placed on pencil line

calculate Rf value by doing the distance the spot moved / distance moved from solvent front

compare with known Rf values to identify pigment

concentrate the spot

Cyclic Photophosphorylation

Photosystem I only

pigments in reaction center absorb light energy and becomes photoactivated

electron becomes excited

taken to electron carrier passing along electron transport chain

causing active transport of H+ into thylakoid membrane and facilitated diffusion back into stroma via ATP synthase (chemiosmosis) which synthesises ATP (ADP +Pi = ATP)

electron is retuned to chlorophyll a molecule

uses of TP

make glucose and/or amino acids and/or sucrose

regenerate RuBP

importance of accessory pigments

extended range of wavelengths

increase efficiency of photosynthesis

absorb light wavelengths other than the blue and red to chlorophyll a

pass energy to reaction center

insulin usage ms

insulin binds to receptors on liver cells

glucose kinase phosphorylates glucose in liver cells

causes glycogenesis

blood glucose concentration decreases

more respiration of glucose

adaptations of PCT

microvilli so PCT has larger surface area

many mitochondria in cells to provide ATP for active transport

many transport proteins for movement of eg, glucose

tight junctions so fluid cannot pass between cells

glucagon and how it works ms

glucagon released from alpha pancreas cells when blood glucose is low

acts on liver cells and triggers glycogenolysis

promotes gluconeogenesis

activates adenylyl cyclase which results in cyclic AMP which acts as secondary messenger

osmoregulation

osmoreceptors detect decrease in water potential which are present in the hypothalamus

ADS released into the blood by posterior pituitary gland

which caused aquaporins to fuse with cell membrane of collecting duct cells resulting in more water being reabsorbed

negative feedback mechanism

detection of change in factor away from set point detected by receptor

hormone released which reaches target cell/effector

so factor returns to set point

glucose biosensor

contains glucose oxidase which catalyses reaction of glucose from the added blood sample

glucose to hydrogen peroxide+ gluconic acid, hydrogen peroxide to O2 + electrons

reaction converted to current being generated which is proportional to glucose concentration

which gives numerical reading

opening of stomata

due to presence of light H+ ions actively transported into guard cell cell wall causing the opening of channel proteins which result in K+ going in

which causes other ions eg Cl- to enter to maintain charge balance decreasing water potential gradient via facilitated diffusion

water enters the guard cell via water potential gradient causing guard cell to become turgid

causing opening/widening of stomata due to thick inner wall

closing of stomata

ABA stops the active transport of H+ ions by binding to its receptor

causes Ca2+ ions to enter cells which results in opening of channel proteins which causes K+ and other ions to leave cell

increase in water potential so water leave guard cell, making it flaccid causing stomatal aperture to close

resting potential ms

active transport via the sodium-potassium pump

moves three Na+ out and 2K+ in (the neuron)

more K+ diffuses out then Na+ diffuses in

so outside of neuron is more positive than the inside

around -70mV

depolarisation ms

+30mV

Na+ ion channel open, causing Na+ ions to move into the cell via facilitated diffusion

repolarisation ms

hyperpolarisation

voltage gated K+ ion channel open allowing K+ ions to diffuse out of neuron

around -90mV

movement of action potential

local circuit/saltatory conduction

from positive area to negative area

synaptic transmission ms

voltage gated Ca2+ ions open due to action potential resulting in Ca2+ ions entering the presynaptic neuron

Ca2+ causes the exocytosis of neurotransmitter eg. Acetyl Choline

neurotransmitter binds to receptor on postsynaptic neuron

opening channels through which sodium can pass into the membrane and depolarise the postsynaptic neuron

Synapse roles

one-way transmission

allows interconnection of multiple pathways and neurones

the power stroke and contraction mechanism

Ca2+ ions bind to troponin

causing tropomyosin to move exposing actin binding site

allowing myosin heads to bind to actin filaments forming cross-bridges

power stroke occurs

Venus Fly Trap adaptations

needs to kill insects due to soil containing few nitrate ions

red lobes to attract insects

mandatory of touching 2 hairs in order to not waste ATP

leaves stay closed for days after insect has been trapped to give time for digestion

Prophase 1 in meiosis + crossing over

homologous chromosomes form bivalents

crossing-over

between non-sister chromatids

chromosomes (stay) joined at chiasmata

independent assortment

metaphase 1

2^n combinations

random orientation

produce different combination of genes in gametes

IUCN ms

international union for conservation of nature

red list

ranks species threat level of extinction

education of public

influence and advise countries to add policies or regulations

PCR

(heat to) 90–98 °C so DNA, denatures

(cool to) 50–65 °C so primers, bind to base pair

(heat to) 68–75 °C so, Taq / DNA, polymerase, makes DNA

repeat cycles to amplify DNA

taq polymerase adaptations

optimum temp higher than DNA polymerase

more heat resistant and less likely to denature

microarrays

probes are short lengths of DNA

complementary to alleles being tested for

sample DNA labelled with fluorescent tags

DNA hybridises and binds to probes

unbound samples of DNA washed off

multiply copies of each probe placed on microarray

SCID therapy get correct one later

gene inserted into stem cell → stem cell divides → daughter cells inherit functional ADA gene → differentiate into immune cells → ADA produced → immune function restored.

crossing over ms

when non-sister chromatids from 2 separate bivalents join together at points called chiasmata

to exchange alleles/genetic information

resulting in new allele combinations

is based on random fusion of gametes

gene mutation and sickle cell anemia

homozygous recessive of the HBB gene

mutation in β globin polypeptide

nucleotide substitution causing polar glutamic acid to be replaced with non-polar valine

resulting in change of tertiary and quaternary structure of haemoglobin

so cells becomes more sickle shaped

how low number of species results in one allele being more frequent or allele being not favoured

founder effect

directional selection

inbreeding

allele frequency for X increases

small gene pool

why water potential of blood may decrease

dehydration/low water intake

more ions or glucose or solutes in the blood

higher rate of sweating of water

non-cyclic photophosphorylation ms

ms for action spectra around the same as absorbance spectra

mention of the highest and lowest peaks (highest at the beginning and end, lowest in the middle)

mention of chlorophyll a using/absorbing this specific wavelength of light (blue(430) and red(640))

mention of how these specific wavelengths are used for photosynthesis

something graph specific

causes of genetic variation

mutation, crossing over, independent assortment and random fertilisation

advantages of using recombinant proteins eg insulin

large supply

no allergic reaction/immune response

cheaper to produce and purify

large scale production

no risk of infection or transmitting diseases

how bioinformatics helps

bioinformatics is a large database of DNA sequence data/search algorithm

to compare with known sequences of DNA in the database

to search for base/protein similar to the one you want

and to predict that protein’s 3D structure

why plasmids can be used as vectors

have marker genes so cells which took up the plasmid can be recognised

have restriction enzyme binding sites

small due to low Mr so can be easily inserted into cell/taken up by it

circular shape makes it stable

genetic engineering ms

takes genes from another species

restriction enzymes cut the gene out of that specie and a plasmid(same for both)

DNA ligase joins the 2 together

forming a recombinant

marker genes used to find out which organism took in the vector

social and ethical implications of GMO

increase food supply thus relieving hunger

increased profits due to lower cost

less herbicides used

unknown/potential side effects

seeds more expensive

decrease in biodiversity

promoter region ms (eukaryotes)

part where RNA polymerase binds

controls when and where the gene expression takes place

creating recombinant for an AAV

correct DNA/allele taken from organism

transcribed into mRNA

checked if correct gene via microarrays and probes/electrophoresis

PCR used to amplify/increase the # of genes

use restriction enzymes and DNA ligase

suggest how errors during PCR can cause mutations

wrong base added

Taq polymerase not proof read

in extension stage

mutation replicated many times

reverse trasncriptase

makes cDNA from mRNA with the help of DNA polymerase dNTP’s ad DNA primers for the second strand

DNA ligase

forms phosphodiester bonds between the vector and gene

restriction enzymes

cut vector and/or plasmid