Genetics

Question 1

What is DNA made of?

Answer 1

Nucleotides

Question 2

What do nucleotides contain?

Answer 2

A sugar phosphate backbone (sugar molecule and phosphate) and a nitrogenous base

Question 3

What are the 4 possible bases and their pairings?

Answer 3

Adenine and Thiamine

Guanine and Cytosine

Question 4

Two polynucleotide strands join together to make a double helix. What type of bond allows this to occur and where are these bonds?

Answer 4

Hydrogen bonds between the nitrogenous bases

3 bonds between GC
2 Bonds between AT

Question 5

How is DNA effectively stored in the nucleus?

Answer 5

DNA molecules are very long and are coiled up very tightly so a lot if genetic information can fit into a small space

Question 6

What structure of DNA makes it efficient at replication?

Answer 6

It has a paired structure which makes it much easier to copy itself - called self-replication.

Question 7

How does the double helix structure help the function?

Answer 7

It makes it very stable in the cell.

Question 8

How is DNA stored in Eukaryotic cells?

Answer 8

DNA is wound into a double helix, then is wound around histone proteins and then coiled up even more into single chromosomes

Question 9

How is DNA stored in Prokaryotic cells?

Answer 9

DNA is wound into a double helix then organised into a circular chromosome which coils up to fit inside the nucleus.

Question 10

DNA contains genes which are instructions for what?

Answer 10

Proteins

Question 11

Each amino acid is coded by a sequence of what?

Answer 11

3 nitrogenous bases ( the triplet code)

Question 12

What is an intron?

what are exons?

Answer 12

Introns - All the parts of DNa that don’t code for amino acids
Exons - all the parts that do

Question 13

What happens to introns during protein synthesis?

Answer 13

They are removed

Question 14

How does DNA determine our nature and development?

Answer 14

DNA determines amino acid sequence
Proteins and enzymes formed
Enzymes enable metabolic pathways
Metabolic pathways help determine our nature and development

Question 15

What is a allele?

Answer 15

An allele is a form of a certain gene

Question 16

How can a gene mutation result in a nonfunctional protein?

Answer 16

Mutation will change the base sequence of DNA
New allele will be produced.
During protein synthesis the new base sequence will code for different amino acids, a non-functional or different protein will be made.
All enzymes are proteins, the new base sequence will change the tertiary structure of the protein which could result in an active site that is the wrong shape- this makes a nonfunctional enzyme (protein)

Question 17

define diploid

Answer 17

a cell that contains 2 sets of chromosomes

Question 18

Define haploid

Answer 18

a cell that contains a single set of chromosomes

Question 19

Define mitosis

Answer 19

A process where a cell is copied. One diploid cell divides to give to identical daughter diploid cells.

Question 20

Define Meiosis

Answer 20

Cell division that creates the sex cells. One diploid cells divides to make four haploid cells - each genetically different.

Question 21

Explain how gametes are formed

Answer 21

Process of meiosis

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