mistakes from mock

Question 1

outline the role of organelles in the production, transport, release of proteins from eukaryotic cells

Answer 1

• vesicles transport proteins for delivery in target
  destinations (1 mark)
• ribosomes undergo protein synthesis (1 mark)
• DNA in the nucleus is code for proteins (1 mark)
• golgi apparatus packages and modifies proteins (1 mark)
• mitochondria produces ATP for protein synthesis

Question 2

why can you not always see the nucleus in an Transmission Electron Micrograph of a plant cell

Answer 2

is a section of the cell so nucleus is in other part of the cell

Question 3

give one advantage of using a transmission electron microscope to view specimen than using a scanning electron microscope

Answer 3

has a shorter wavelength so you can see internal structures

Question 4

define exon

Answer 4

base sequence coding for sequence of amino acids

Question 5

the original amino acid sequence was

serine alanine glycine proline

a mutation results in this chain

serine glycine glycine proline

the student concluded the mutation was an addition. does the information in the question support the student conclusion. give reasons for your answer

Answer 5

no G/C substitution

or

frameshift

affect more than 1 a/a

Question 6

describe how the structure of a protein depends on the amino acids it contains

Answer 6

1. the structure of protein is determined by the position of amino acids/ R group/ interactions
2. the primary structure is the sequence of amino acids
3. the secondary structure is formed by H bonds between amino acids (alpha helicases and beta pleated sheets)
4. the tertiary structure is formed by H bonds, ionic bonds, disulfide bridges giving the protein it’s 3d structure
5. this creates the active site in enzymes
   or
   creates specific shape in antibodies/ receptors/ carrier proteins
6. the quaternary structure contains more than 1 type of polypeptide chain

Question 7

explain the arrangement of phospholipids in the cell surface membrane

Answer 7

• the cell membrane is made up of a phospholipid bilayer (1 mark)
• hydrophobic tails point inwards repelled by water and hydrophilic heads point outwards as they are attracted to water

Question 8

describe how an ester bond is formed in a phospholipid molecule

Answer 8

• an ester bond is formed during a condensation reaction (1 mark)
• between the fatty acid and glycerol molecule

Question 9

state and explain the property of water that helps to prevent temperature increase in a cell

Answer 9

high specific heat capacity

takes a lot of energy to change the temperature of the cell by 1 degree therefore making water stable

Question 10

define uncertainty

Answer 10

the level of doubt in precision of measurement obtained

Question 11

what is the equation for percentage error

Answer 11

(maximum error/ measured value ) x 100