AQA A LEVEL BIOLOGY QUESTIONS AND ANSWERS|
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GRADED A+
1 molecules of glucose krebs yield - Correct Answer ✅💯6 reduced NAD
2 reduced FAD
2 ATP
4 CO2
1 turn of krebs yield - Correct Answer ✅💯3 reduced NAD
1 reduced FAD
1 ATP
2x heterozygous B - Correct Answer ✅💯3:1
75% B, 25% O
5 assumptions of hardy-weinburg principle - Correct Answer ✅💯- large breeding
population
- random mating
- no change in allelic frequency due to mutation
- no immigration or emigration
- no natural selection
abiotic - Correct Answer ✅💯non-living factor e.g oxygen in a pond
abiotic factors examples - Correct Answer ✅💯- availability of water and resources
- season
- climate/temp
- geographical barriers/ terrain
- fertility of soil
- humidity
active immunity characteristics - Correct Answer ✅💯- requires exposure to antigen
- takes a while for production to develop
- memory cells produced
- long-term protection
,active transport - Correct Answer ✅💯transport of molecules or ions from an area of lower
to higher conc against the conc gradient using a carrier protein across a partially permeable
membrane and requires ATP
advancements in technology that can clarify evolutionary relationships - Correct Answer
✅💯genome sequencing = higher % of DNA similarity = closely related
comparing amino acid sequence = related organisms have similar amino acid sequences
immunological comparison = similar proteins will bind the same antibodies
advances in what have helped to clarify evolutionary relationships between organisms? -
Correct Answer ✅💯- immunology
- genome sequencing
aerobic chemical equation - Correct Answer ✅💯C₆H₁₂O₆ + 6O₂ = 6H₂0 + 6CO₂
aerobic respiration - Correct Answer ✅💯requires oxygen and produces co2, water and ATP
agricultural impacts on biodiversity - Correct Answer ✅💯ecosystem = cut down forests for
farmland so less biodiversity
reduction of no of habitats through growing crops
filling in ponds or runoff destroys habitats
genetic = pick the best crop, other varieties die out as they aren't wanted
best grower outcompete due to selective breeding and restrict gene pool
GM
species = removing habitats decrease no of animals that can live there, species grow on farms
e.g cows, wheat = other species have to compete for limited resources
agricultural practices that reduce biodiversity - Correct Answer ✅💯- woodland clearance
reduces no of trees = destroys habitats
- hedgerow removal makes small fields into larger fields = destroys habitats
- pesticides kill organisms
- herbicides kill weeds = reduced plant diversity which reduces the no of organisms that feed
on weeds
- monoculture when fields contain one plant type = reduces diversity by supporting fewer
organisms
,allopatric speciation - Correct Answer ✅💯- GEOGRAPHICAL ISOLATION
- no gene flow - no interbreeding
- independent alleles - beneficial alleles
- beneficial alleles passed on
- if reintroduce - no fertile offspring
amino acid structure - Correct Answer ✅💯H N O
\ | //
N-C-O
/|\
H R OH
anaerobic respiration - Correct Answer ✅💯takes place in the absence of oxygen and
produces lactate (animals) or ethanol and co2 (plants and fungi) but only little ATP
anaerobic respiration equation - Correct Answer ✅💯pyruvate + reduced NAD = lactate +
NAD
anaerobic respiration in plants/fungi/bacteria - Correct Answer ✅💯pyruvate + reduced
NAD = ethanol + CO2 + NAD
anaphase - Correct Answer ✅💯- paired chromosomes separate at centromeres
- move to opposite sides
anion - Correct Answer ✅💯atom with a negative charge
antibiotics and microbial growth required practical - Correct Answer ✅💯1. agar plate with
liquid broth
2. use sterile pipette to transfer bacteria and spread with spreader
3. use forces to place antibiotic soaked disk in plate
add another disk to water as control
4. tape lid and store at 25 degrees for 48hrs
5. size of inhibition zone tells you effectiveness of antibiotic
antibodies - Correct Answer ✅💯- immune response
- 2 light and 2 heavy polypeptide chains bonded together
- variable region
^ amino acid sequence in region vary
aphids supporting evidence for mass flow theory - Correct Answer ✅💯- aphids pierce
phloem and leave mouthparts behind so sap can flow out
, - sap flows out quicker near the leaves than further down the stem
= pressure gradient
aseptic techniques - Correct Answer ✅💯- prevent contamination
- regularly disinfect work surfaces
- sterilise equipment using bunsen or autoclave
- work near bunsen as hot air rises so microbes are drawn away from culture
- minimise time with lid off plate
- flame neck of broth
at which stage do chromosomes replicate? - Correct Answer ✅💯interphase before prophase
1
autosomal linkage - Correct Answer ✅💯- if genes A and B occur on separate chromosomes
they are NOT linked
- if genes A and B occur on the same chromosome they ARE linked
bacteria death phase - Correct Answer ✅💯- living bacteria decreases over time due to lack
of nutrients and toxic metabolic by-products
bacteria exponential phase - Correct Answer ✅💯- size of bacteria population increases
- exponential growth
bacteria lag phase - Correct Answer ✅💯- bacteria adjust to new environment e.g
synthesising the correct enzymes
- no significant increase in numbers
bacteria stationary phase - Correct Answer ✅💯- nutrients run out and waste products build
up - ENVIROMENTAL RESISTANCE
- no net growth
bases found in DNA - Correct Answer ✅💯- adenine
- guanine
- cytosine
- thymine
biodiversity - Correct Answer ✅💯- general term used to describe variety in the living
world
- refers to number and variety of living organisms ina particular area
- species, genetic and ecosystem diversity
biotic - Correct Answer ✅💯living factor
DOWNLOADED TO SCORE A PERFECT SCORE|
GRADED A+
1 molecules of glucose krebs yield - Correct Answer ✅💯6 reduced NAD
2 reduced FAD
2 ATP
4 CO2
1 turn of krebs yield - Correct Answer ✅💯3 reduced NAD
1 reduced FAD
1 ATP
2x heterozygous B - Correct Answer ✅💯3:1
75% B, 25% O
5 assumptions of hardy-weinburg principle - Correct Answer ✅💯- large breeding
population
- random mating
- no change in allelic frequency due to mutation
- no immigration or emigration
- no natural selection
abiotic - Correct Answer ✅💯non-living factor e.g oxygen in a pond
abiotic factors examples - Correct Answer ✅💯- availability of water and resources
- season
- climate/temp
- geographical barriers/ terrain
- fertility of soil
- humidity
active immunity characteristics - Correct Answer ✅💯- requires exposure to antigen
- takes a while for production to develop
- memory cells produced
- long-term protection
,active transport - Correct Answer ✅💯transport of molecules or ions from an area of lower
to higher conc against the conc gradient using a carrier protein across a partially permeable
membrane and requires ATP
advancements in technology that can clarify evolutionary relationships - Correct Answer
✅💯genome sequencing = higher % of DNA similarity = closely related
comparing amino acid sequence = related organisms have similar amino acid sequences
immunological comparison = similar proteins will bind the same antibodies
advances in what have helped to clarify evolutionary relationships between organisms? -
Correct Answer ✅💯- immunology
- genome sequencing
aerobic chemical equation - Correct Answer ✅💯C₆H₁₂O₆ + 6O₂ = 6H₂0 + 6CO₂
aerobic respiration - Correct Answer ✅💯requires oxygen and produces co2, water and ATP
agricultural impacts on biodiversity - Correct Answer ✅💯ecosystem = cut down forests for
farmland so less biodiversity
reduction of no of habitats through growing crops
filling in ponds or runoff destroys habitats
genetic = pick the best crop, other varieties die out as they aren't wanted
best grower outcompete due to selective breeding and restrict gene pool
GM
species = removing habitats decrease no of animals that can live there, species grow on farms
e.g cows, wheat = other species have to compete for limited resources
agricultural practices that reduce biodiversity - Correct Answer ✅💯- woodland clearance
reduces no of trees = destroys habitats
- hedgerow removal makes small fields into larger fields = destroys habitats
- pesticides kill organisms
- herbicides kill weeds = reduced plant diversity which reduces the no of organisms that feed
on weeds
- monoculture when fields contain one plant type = reduces diversity by supporting fewer
organisms
,allopatric speciation - Correct Answer ✅💯- GEOGRAPHICAL ISOLATION
- no gene flow - no interbreeding
- independent alleles - beneficial alleles
- beneficial alleles passed on
- if reintroduce - no fertile offspring
amino acid structure - Correct Answer ✅💯H N O
\ | //
N-C-O
/|\
H R OH
anaerobic respiration - Correct Answer ✅💯takes place in the absence of oxygen and
produces lactate (animals) or ethanol and co2 (plants and fungi) but only little ATP
anaerobic respiration equation - Correct Answer ✅💯pyruvate + reduced NAD = lactate +
NAD
anaerobic respiration in plants/fungi/bacteria - Correct Answer ✅💯pyruvate + reduced
NAD = ethanol + CO2 + NAD
anaphase - Correct Answer ✅💯- paired chromosomes separate at centromeres
- move to opposite sides
anion - Correct Answer ✅💯atom with a negative charge
antibiotics and microbial growth required practical - Correct Answer ✅💯1. agar plate with
liquid broth
2. use sterile pipette to transfer bacteria and spread with spreader
3. use forces to place antibiotic soaked disk in plate
add another disk to water as control
4. tape lid and store at 25 degrees for 48hrs
5. size of inhibition zone tells you effectiveness of antibiotic
antibodies - Correct Answer ✅💯- immune response
- 2 light and 2 heavy polypeptide chains bonded together
- variable region
^ amino acid sequence in region vary
aphids supporting evidence for mass flow theory - Correct Answer ✅💯- aphids pierce
phloem and leave mouthparts behind so sap can flow out
, - sap flows out quicker near the leaves than further down the stem
= pressure gradient
aseptic techniques - Correct Answer ✅💯- prevent contamination
- regularly disinfect work surfaces
- sterilise equipment using bunsen or autoclave
- work near bunsen as hot air rises so microbes are drawn away from culture
- minimise time with lid off plate
- flame neck of broth
at which stage do chromosomes replicate? - Correct Answer ✅💯interphase before prophase
1
autosomal linkage - Correct Answer ✅💯- if genes A and B occur on separate chromosomes
they are NOT linked
- if genes A and B occur on the same chromosome they ARE linked
bacteria death phase - Correct Answer ✅💯- living bacteria decreases over time due to lack
of nutrients and toxic metabolic by-products
bacteria exponential phase - Correct Answer ✅💯- size of bacteria population increases
- exponential growth
bacteria lag phase - Correct Answer ✅💯- bacteria adjust to new environment e.g
synthesising the correct enzymes
- no significant increase in numbers
bacteria stationary phase - Correct Answer ✅💯- nutrients run out and waste products build
up - ENVIROMENTAL RESISTANCE
- no net growth
bases found in DNA - Correct Answer ✅💯- adenine
- guanine
- cytosine
- thymine
biodiversity - Correct Answer ✅💯- general term used to describe variety in the living
world
- refers to number and variety of living organisms ina particular area
- species, genetic and ecosystem diversity
biotic - Correct Answer ✅💯living factor
