AQA A+level Biology paper 1 Q and A
Solutions
Benedict's test - ANS-Which food test is heated in a water bath?
Sucrose - ANS-Which disaccharide is not a reducing sugar?
Test for non-reducing sugars - ANS-Add acid. Neutralise. Add Benedicts. Heat.
Hydrolysis - ANS-Reaction performed by dilute HCl in the non reducing sugar test.
Glucose + fructose - ANS-During the non-reducing sugar test what is sucrose
hydrolysed into?
Alpha - ANS-Which type of glucose makes up starch?
amylose and amylopectin - ANS-Names of two types of starch
Amylose - ANS-Coiled, compact form of starch. Stored easily.
Amylopectin - ANS-Branched form of starch. More easily hydrolysed.
surface area - ANS-Branched carbohydrates have a higher _____ for enzymes to work
on.
Glycogen - ANS-Carbohydrate store in animals
branched - ANS-Glycogen is....
metabolic rate - ANS-Glycogen is more branched than amylopectin because animals
have a higher _____________
osmotically inactive. - ANS-Starch is insoluble and therefore ....
Beta - ANS-What type of glucose is cellulose made from?
,Alpha and beta glucose - ANS-H and OH swapped on Carbon 1.
Fibrils - ANS-Cellulose forms long chains called...
H bonds - ANS-Cellulose molecules are crosslinked by
strength - ANS-Cross linking of cellulose molecules gives them...
Triglycerides - ANS-_______ are a good source of energy because they have a high
ratio of energy-storing carbon-hydrogen bonds
what are the roles of lipids? - ANS-1. source of energy
2. waterproofing
3. insulation
4. protection
how does the structure of phospholipids relate to their properties? - ANS-1. polar,
therefore will position itself to form a bilayer
2. the structure allows them to form glycolipids by combining with carbohydrates within
the cell-surface membrane. these are important in cell recognition.
draw the structure of an amino acid - ANS
draw how a dipeptide forms - ANS
what is meant by 'primary sequence' of a protein - ANS-The unique sequence of amino
acids that make up a protein or polypeptide chain
what is meant by 'secondary sequence' of a protein - ANS-The way in which the primary
structure of a polypeptide chain folds e.g. alpha helix or beta pleated sheets. shape is
held by H bonds.
what is meant by 'tertiary sequence' of a protein - ANS-This is the overall 3-D structure
of the protein.
The shape of the protein is held together by H bonds and ionic bonds and disulfide
bridges.
what is meant by 'quaternary sequence' of a protein - ANS-If a protein is made up of
several polypeptide chains that are linked in various ways, the way they are arranged is
, called the quaternary structure.
Biuret is made up of... - ANS-equal volumes and copper sulphate and sodium hydroxide
what are fiberous proteins made up of? - ANS-made of long molecules arranged to form
fibres (e.g. in keratin). Several helices may be wound around each other to form very
strong fibres.
what are globular proteins made up of? - ANS-made of chains folded into a compact
structure. One of the most important classes are the enzymes. Although these folds are
less regular than in a helix, they are highly specific and a particular protein will always
be folded in the same way.
what kind of protein is collagen? - ANS-fibrous
what kind of protein is haemoglobin? - ANS-globular
what is haemoglobin made up of? - ANS-two α polypeptide chains
two β polypeptide chains
an inorganic prosthetic haem group (Fe2+)
Describe the structure of collagen. - ANS-three polypeptide chains wound around each
other. Hydrogen bonds form between these chains. Coils forms Covalent Cross Links
with each other. Covalent cross links are staggered.
what are the functions of collagen? - ANS-1. Form the structure of bones
2. Makes up cartilage and connective tissue
3. Prevents blood that is being pumped at high pressure from bursting the walls of
arteries
4. Is the main component of tendons, which connect skeletal muscles to bones
what type of bond forms between the phosphate group and deoxyribose sugar in DNA?
- ANS-phosphodiester bond
why is DNA stable? - ANS-1. the phosphodiester backbone protects the more
chemically reactive organic bases inside the double helix
2. many hydrogen bonds link the base pairs together, so it adds strength overall.
how is DNA adapted to carrying out its function? - ANS-1. it is very stable, thus rarely
mutates
Solutions
Benedict's test - ANS-Which food test is heated in a water bath?
Sucrose - ANS-Which disaccharide is not a reducing sugar?
Test for non-reducing sugars - ANS-Add acid. Neutralise. Add Benedicts. Heat.
Hydrolysis - ANS-Reaction performed by dilute HCl in the non reducing sugar test.
Glucose + fructose - ANS-During the non-reducing sugar test what is sucrose
hydrolysed into?
Alpha - ANS-Which type of glucose makes up starch?
amylose and amylopectin - ANS-Names of two types of starch
Amylose - ANS-Coiled, compact form of starch. Stored easily.
Amylopectin - ANS-Branched form of starch. More easily hydrolysed.
surface area - ANS-Branched carbohydrates have a higher _____ for enzymes to work
on.
Glycogen - ANS-Carbohydrate store in animals
branched - ANS-Glycogen is....
metabolic rate - ANS-Glycogen is more branched than amylopectin because animals
have a higher _____________
osmotically inactive. - ANS-Starch is insoluble and therefore ....
Beta - ANS-What type of glucose is cellulose made from?
,Alpha and beta glucose - ANS-H and OH swapped on Carbon 1.
Fibrils - ANS-Cellulose forms long chains called...
H bonds - ANS-Cellulose molecules are crosslinked by
strength - ANS-Cross linking of cellulose molecules gives them...
Triglycerides - ANS-_______ are a good source of energy because they have a high
ratio of energy-storing carbon-hydrogen bonds
what are the roles of lipids? - ANS-1. source of energy
2. waterproofing
3. insulation
4. protection
how does the structure of phospholipids relate to their properties? - ANS-1. polar,
therefore will position itself to form a bilayer
2. the structure allows them to form glycolipids by combining with carbohydrates within
the cell-surface membrane. these are important in cell recognition.
draw the structure of an amino acid - ANS
draw how a dipeptide forms - ANS
what is meant by 'primary sequence' of a protein - ANS-The unique sequence of amino
acids that make up a protein or polypeptide chain
what is meant by 'secondary sequence' of a protein - ANS-The way in which the primary
structure of a polypeptide chain folds e.g. alpha helix or beta pleated sheets. shape is
held by H bonds.
what is meant by 'tertiary sequence' of a protein - ANS-This is the overall 3-D structure
of the protein.
The shape of the protein is held together by H bonds and ionic bonds and disulfide
bridges.
what is meant by 'quaternary sequence' of a protein - ANS-If a protein is made up of
several polypeptide chains that are linked in various ways, the way they are arranged is
, called the quaternary structure.
Biuret is made up of... - ANS-equal volumes and copper sulphate and sodium hydroxide
what are fiberous proteins made up of? - ANS-made of long molecules arranged to form
fibres (e.g. in keratin). Several helices may be wound around each other to form very
strong fibres.
what are globular proteins made up of? - ANS-made of chains folded into a compact
structure. One of the most important classes are the enzymes. Although these folds are
less regular than in a helix, they are highly specific and a particular protein will always
be folded in the same way.
what kind of protein is collagen? - ANS-fibrous
what kind of protein is haemoglobin? - ANS-globular
what is haemoglobin made up of? - ANS-two α polypeptide chains
two β polypeptide chains
an inorganic prosthetic haem group (Fe2+)
Describe the structure of collagen. - ANS-three polypeptide chains wound around each
other. Hydrogen bonds form between these chains. Coils forms Covalent Cross Links
with each other. Covalent cross links are staggered.
what are the functions of collagen? - ANS-1. Form the structure of bones
2. Makes up cartilage and connective tissue
3. Prevents blood that is being pumped at high pressure from bursting the walls of
arteries
4. Is the main component of tendons, which connect skeletal muscles to bones
what type of bond forms between the phosphate group and deoxyribose sugar in DNA?
- ANS-phosphodiester bond
why is DNA stable? - ANS-1. the phosphodiester backbone protects the more
chemically reactive organic bases inside the double helix
2. many hydrogen bonds link the base pairs together, so it adds strength overall.
how is DNA adapted to carrying out its function? - ANS-1. it is very stable, thus rarely
mutates
