Genetics

Question 1

Which row describes the sperm cell and the egg cell before fertilisation?

Answer 1

Haploid, Haploid

Question 2

Describe the structure of DNA.

Answer 2

DNA is a double helix, sugar phosphate backbone, A-T AND C-G, hydrogen bonds

Question 3

Describe how this mRNA strand is then used to make proteins.

Answer 3

process is translation/ mRna leves the nucleus into the cytoplasm/ mRNA joins to ribosome/ bases are read as triplets

Question 4

Describe how the two strands of a DNA molecule are linked together.

Answer 4

Hydrogen bonds/ complementary base pairs

Question 5

Name the structure where translation occurs.

Answer 5

Ribosome

Question 6

Name the type of cell division that results in the production of these new plants.

Answer 6

Mitosis

Question 7

Farmers cut the runners and sell the new plants.

Suggest advantages of producing new strawberry plants in this way.

Answer 7

easier to generate new plants/ quicker/ cheaper

Question 8

Suggest the purpose of stages 1 (Grinding strawberries) and 3 (add ethanol) in the DNA extraction.

Answer 8

• break open cells to release DNA

- separate DNA

Question 9

Describe how a section of DNA determines the structure of a protein.

Answer 9

sequence of bases determines sequence of amino acids/ 3 bases for 1 amino acid/ lots of amino acids make up a polypeptide/ transcription

Question 10

Describe the structure of DNA, including the roles of the scientists involved in its discovery.

Answer 10

two strands/ double helix/ complementary bases/ a, t, c, g/ a and t, c and g/ x ray crystallography/ shows helical structure/ shows diameter/shows how base pairs are arranged.

Question 11

Explain how the Human Genome Project has contributed to advances in medicine.

Answer 11

identification of faulty or mutated genes/ development of gene therapy/ people can be tested for a genetic disorder

Question 12

These amino acids will be joined together during protein synthesis. During which stage of protein synthesis will this take place?

Answer 12

Translation

Question 13

Amino acids are joined together

Answer 13

Ribosome

Question 14

Explain the role of the active site of an enzyme.

Answer 14

enzyme/ active site needs to be specific shape/ to bind to enzyme/ reaction takes place or is catalysed

Question 15

Describe what effect a mutation could have on the action of an enzyme.

Answer 15

mutation is a cange of DNA sequence/ a change in dna means a change in amino acids, or chnage in order/ changes shape of active site, enzyme, protien

Question 16

Explain how two parents with a dominant phenotype can produce offspring expressing a recessive characteristic.

Answer 16

both parents must be hetrozygous for the recessive allele/ so the offspring must inherit the recessive allele from each parent

Question 17

State the genotype of Rani.

Answer 17

hetrozygous

Question 18

Explain why the CD4+ count of 1.5 × 108 cells/dm3 has led to the diagnosis of AIDS.

Answer 18

the cd4+ count is significanlty below the normal range because the HIV has destroyed the cd4+ cells so more susctipble to catching other diseases which is classified as having AIDS