Mock corrections

Question 1

Inorganic Ions

Answer 1

-Calcium Pectate- cell walls
•Magnesium- enzymes and chlorophyll
•Iron- haemoglobin and electron carriers
•Hydrogen Carbonate- Buffer
•Nitrate- amino acids, nucleic acids and chlorophyll
•Phosphate- phosphate salts, buffer, cell membranes and nucleotides

Question 2

Structure of an amino acid

Answer 2

•AMINO group- NH2

•HYDROGEN group- H

•CARBOXYL group- COOH

•VARIABLE group- R

Question 3

PRIMARY Structure

Answer 3

The sequence of amino acids in the polypeptide chain- held tg by peptide bonds

Question 4

SECONDARY Structure

Answer 4

The way the polypeptide chain coils/ folds- form a- helix or B pleated sheet

HYDROGEN bonds- hold the structures together

Question 5

Conjugated Protein

Answer 5

Fibrous- main function- support for a structural role- strong- due to the presence of many cross links- ‘rope’ structure
-Insoluble and stable
•3 polypeptide chains coiled around each other- triple helix
•cross link between chains and molecules create the strength

Question 6

Enzymes

Answer 6

•TEMPERATURE- increased kinetic energy-molecules move faster- more collisions- more ESC formed
•above optimum- enzyme becomes denatured- internal HYDROGEN bonds, which maintain the active site shape, are broken

Question 7

PH

Answer 7

As pH increases, rate of reaction increases- higher pH- enzyme becomes denatured- bonds (IONIC), determine the proteins 3D, tertiary structure/ shape become disrupted- DENATURATION

Question 8

NUCLEIC ACIDS

Answer 8

•consist of
-pentose sugar
-nitrogenous base
-phosphate

COMPARE AND CONTRAST DNA AND RNA
•DNA- found in nucleus, RNA- found in cytoplasm
•DNA- A + T, C+ G, RNA- A+U, C+G
•DNA- deoxyribose sugar, RNA- ribose sugar
•DNA- longer/ more based
•RNA- 3 types- mRNA, tRNA and rRNA
•DNA- double chain, RNA- single chain

Question 9

SEMI CONSERVATIVE REPLICATION

Answer 9

•Enzyme DNA HELICASE unwinds the DNA double helix by BREAKUNG THE HYDROGEN BONDS
•Each strand acts as a template for the synthesis of a new strand- exposed bases bind to free floating nucleotides in the nucleoplasm
•DNA POLYMERASE- binds the complementary nucleotides to the exposed bases on the template strand- this continues along the whole DNA- form new complementary strands

Question 10

PRACTICALS

Answer 10

Same. Control
Alter. Independent
Measure. Dependant

Question 11

Describe the mechanism of enzymes

Answer 11

•form ESC- more collisions
•activation energy lowered
•active site changes shape- products repelled from active site- different shape

Question 12

Why DNA replicates before dividing?

Answer 12

•To ensure the full DNA component is in each daughter cell