AQA A-level Biology paper 1 .2025.
3.1.5.2 - correct answerDNA REPLICATION
a change in pH alters the charges on the amino acids that make up the active site of the enzyme, as a
result ... - correct answerthe substrate cant become attached to the active site, meaning the enzyme-
substrate complex cannot be formed
A functional protein may contain ... - correct answerOne or more polypeptides
a proteins shape is very specific to its function, change it and ... - correct answerit will function less well
or differently
a significant change in pH may cause what in an enzymes tertiary structure? - correct answerbonds to
break and the active site to change shape
A single molecule of ATP is a ... - correct answerNucleotide derivative
Adenine diphosphate - correct answerADP
Adenosine triphosphate - correct answerATP
all cells in an organism are produced by ... - correct answermitotic divisions from the fertilised egg
All life on earth shares a common chemistry ... - correct answerThis provides indirect evidence for
evolution
all membranes around and within all cells have the same basic structure, what are they known as? -
correct answerplasma membranes
,An RNA molecule is a ... - correct answerRelatively short polynucleotide chain
as long as there is excess of substrate, an increase in the amount of enzyme leads to ... - correct answera
proportionate increase in the rate of reaction
B lympocytes = - correct answerB cells
before a nucleus divides, what must happen? - correct answerits DNA needs to be replicated
before cell fractionation the tissue is placed in a buffered solution, why? - correct answerto prevent the
pH fluctuating - this could alter the structure of organelles or affect the functioning of enzymes
before cell fractionation the tissue is placed in a cold solution, why? - correct answerto reduce enzyme
activity that might break down the organelles
before cell fractionation the tissue is placed in a solution of the same water potential as the tissue, why?
- correct answerto prevent organelles bursting or shrinking as a result of osmotic gain or loss of water
before the induced fit model how were enzymes thought to work? - correct answerthe lock and key
model
being non-living, what do viruses not undergo? - correct answercell division
Carbohydrates are commonly used by cells as respiratory substrates, - correct answerThey also form
structural components in plasma membranes and cell walls
cells become specialised in structure to ... - correct answersuit the role it will carry out
cells may be adapted for rapid transport across their internal or external membranes by ... - correct
answeran increase in surface area, the number of protein channels and carrier channels in their
membrane
,cellulose is a major component of plant cell walls and provides ... - correct answerrigidity to the plant
cell
Deoxyribonucleic acid - correct answerDNA
ER - correct answerendoplasmic reticulum
eukaryotic cells are ... - correct answerlarger and have a nucleus bounder by nuclear membranes
examples of tissues include: - correct answerepithelial tissues, xylem
facilitated diffusion - correct answerMovement of specific molecules across cell membranes through
protein channels
for a pathogen to infect the body it must first gain entry, what is the bodys first line of defence? - correct
answera form of physical or chemical barrier to entry
for an enzyme to work, it must ... - correct answercome into physical contact with its substrate
have an active site which fits the substrate
how are chloroplasts adapted to their function of harvesting sunlight and carrying out photosynthesis? -
correct answergranal membranes provide a large surface area, the stroma possess all the enzymes
needed for the second stage of photosynthesis, chloroplasts contain the DNA and ribosomes needed to
quickly manufacture proteins needed for photosynthesis
How are dipeptides formed? - correct answerThe condensation of two amino acids
how are disaccharides formed? - correct answerThe condensation of two monosaccharides
how are DNAs two nucleotide strands joined together? - correct answerhydrogen bonds
, how are enzymes effective in small amounts? - correct answerthey can be reused repeatedly
How are polypeptides formed? - correct answerThe condensation of many amino acids
How are triglycerides formed? - correct answerCondensation of one molecule of glycerol and three
molecules of fatty acid
how can T cells distinguish invader cells from normal cells? - correct answerthe different antigens
present on the cell-surface membrane
how can viruses multiply? - correct answerinside a living host cell
how do cytotoxic T cells kill infected cells? - correct answerby producing perforin
how do drugs used to treat cancer usually disrupt the cell cycle? - correct answerpreventing DNA from
replicating, inhibiting the metaphase stage of mitosis by interfering with spindle formation
how do prokaryotic cells differ from eukaryotic cells? - correct answercytoplasm that lacks membrane
bound organelles, smaller ribosomes, no nucleus - instead a single circular DNA molecule, a cell wall that
contains murein, one or more plasmids, a capsule surrounding the cell, one or more flagella
How do the twenty amino acids that are common in all organisms differ? - correct answerOnly in their
side group
how do viruses replicate? - correct answerby attatching to their host cell with the attachment proteins
on their surface, they then inject their nucleic acid into the host cell, this provides 'instructions' for the
host cells metabolic processes to start producing the viral components
how do you calibrate the eyepiece graticule? - correct answeruse the stage micrometer with the
eyepiece graticule to work out the scale
how do you carry out the benedicts test? - correct answer1. dissolve the food sample in water
3.1.5.2 - correct answerDNA REPLICATION
a change in pH alters the charges on the amino acids that make up the active site of the enzyme, as a
result ... - correct answerthe substrate cant become attached to the active site, meaning the enzyme-
substrate complex cannot be formed
A functional protein may contain ... - correct answerOne or more polypeptides
a proteins shape is very specific to its function, change it and ... - correct answerit will function less well
or differently
a significant change in pH may cause what in an enzymes tertiary structure? - correct answerbonds to
break and the active site to change shape
A single molecule of ATP is a ... - correct answerNucleotide derivative
Adenine diphosphate - correct answerADP
Adenosine triphosphate - correct answerATP
all cells in an organism are produced by ... - correct answermitotic divisions from the fertilised egg
All life on earth shares a common chemistry ... - correct answerThis provides indirect evidence for
evolution
all membranes around and within all cells have the same basic structure, what are they known as? -
correct answerplasma membranes
,An RNA molecule is a ... - correct answerRelatively short polynucleotide chain
as long as there is excess of substrate, an increase in the amount of enzyme leads to ... - correct answera
proportionate increase in the rate of reaction
B lympocytes = - correct answerB cells
before a nucleus divides, what must happen? - correct answerits DNA needs to be replicated
before cell fractionation the tissue is placed in a buffered solution, why? - correct answerto prevent the
pH fluctuating - this could alter the structure of organelles or affect the functioning of enzymes
before cell fractionation the tissue is placed in a cold solution, why? - correct answerto reduce enzyme
activity that might break down the organelles
before cell fractionation the tissue is placed in a solution of the same water potential as the tissue, why?
- correct answerto prevent organelles bursting or shrinking as a result of osmotic gain or loss of water
before the induced fit model how were enzymes thought to work? - correct answerthe lock and key
model
being non-living, what do viruses not undergo? - correct answercell division
Carbohydrates are commonly used by cells as respiratory substrates, - correct answerThey also form
structural components in plasma membranes and cell walls
cells become specialised in structure to ... - correct answersuit the role it will carry out
cells may be adapted for rapid transport across their internal or external membranes by ... - correct
answeran increase in surface area, the number of protein channels and carrier channels in their
membrane
,cellulose is a major component of plant cell walls and provides ... - correct answerrigidity to the plant
cell
Deoxyribonucleic acid - correct answerDNA
ER - correct answerendoplasmic reticulum
eukaryotic cells are ... - correct answerlarger and have a nucleus bounder by nuclear membranes
examples of tissues include: - correct answerepithelial tissues, xylem
facilitated diffusion - correct answerMovement of specific molecules across cell membranes through
protein channels
for a pathogen to infect the body it must first gain entry, what is the bodys first line of defence? - correct
answera form of physical or chemical barrier to entry
for an enzyme to work, it must ... - correct answercome into physical contact with its substrate
have an active site which fits the substrate
how are chloroplasts adapted to their function of harvesting sunlight and carrying out photosynthesis? -
correct answergranal membranes provide a large surface area, the stroma possess all the enzymes
needed for the second stage of photosynthesis, chloroplasts contain the DNA and ribosomes needed to
quickly manufacture proteins needed for photosynthesis
How are dipeptides formed? - correct answerThe condensation of two amino acids
how are disaccharides formed? - correct answerThe condensation of two monosaccharides
how are DNAs two nucleotide strands joined together? - correct answerhydrogen bonds
, how are enzymes effective in small amounts? - correct answerthey can be reused repeatedly
How are polypeptides formed? - correct answerThe condensation of many amino acids
How are triglycerides formed? - correct answerCondensation of one molecule of glycerol and three
molecules of fatty acid
how can T cells distinguish invader cells from normal cells? - correct answerthe different antigens
present on the cell-surface membrane
how can viruses multiply? - correct answerinside a living host cell
how do cytotoxic T cells kill infected cells? - correct answerby producing perforin
how do drugs used to treat cancer usually disrupt the cell cycle? - correct answerpreventing DNA from
replicating, inhibiting the metaphase stage of mitosis by interfering with spindle formation
how do prokaryotic cells differ from eukaryotic cells? - correct answercytoplasm that lacks membrane
bound organelles, smaller ribosomes, no nucleus - instead a single circular DNA molecule, a cell wall that
contains murein, one or more plasmids, a capsule surrounding the cell, one or more flagella
How do the twenty amino acids that are common in all organisms differ? - correct answerOnly in their
side group
how do viruses replicate? - correct answerby attatching to their host cell with the attachment proteins
on their surface, they then inject their nucleic acid into the host cell, this provides 'instructions' for the
host cells metabolic processes to start producing the viral components
how do you calibrate the eyepiece graticule? - correct answeruse the stage micrometer with the
eyepiece graticule to work out the scale
how do you carry out the benedicts test? - correct answer1. dissolve the food sample in water
