DNA Structure, Mutation and Inheritance 2.5, 2.12, 2.13

Question 1

What is the function of DNA?

Answer 1

It’s a store of genetic information containing all the instructions an organism needs to grow and develop

Question 2

What is the function of RNA?

Answer 2

Transfer genetic information from DNA to ribsosomes

Question 3

What organelle is made from RNA and proteins?

Answer 3

Ribsosomes

Question 4

Describe a mononucleotide

Answer 4

A pentose sugar (5 carbon) attached to a nitrogenous base and a phosphate group

Question 5

Define DNA/RNA

Answer 5

Polynucleotides composed of mono nucleotides linked by condensation reaction

Question 6

Describe the structure of a DNA molecule

Answer 6

Double helix with two polynucleotide chains consisting of a sugar phosphate backbone held together by hydrogen bonds between the complementary bases

Question 7

What is a polynucleotide

Answer 7

A polymer of mononucleotides

Question 8

How are mononucleotides joined - what is the byproduct?

Answer 8

Condensation reaction between the phosphate of one mononucleotide and the sugar group of another
Water is a byproduct

Question 9

How many hydrogen bonds between A and T bases

Answer 9

A and T = 2 hydrogen bonds

C and G = 3 hydrogen bonds

Question 10

What is a mutation?

Answer 10

A change to the base sequence of DNA that can be causes by errors during DNA replication

Question 11

Name the 5 types of mutation

Answer 11

Substitution 
Deletion
Insertion
Duplication 
Inversion (sequence of bases is inverted)

Question 12

How can a mutation affect a protein?

Answer 12

The order of DNA bases determines the order of amino acids which makes up the primary structure of a protein and thus therefore could be altered, changing the final 3D shape of the protein

Question 13

How many possible mutations are thought to cause CF?

Answer 13

Over 1000

Question 14

Define a ‘gene’

Answer 14

A sequence of bases on a DNA molecule that codes for a protein

Question 15

Define ‘allele’

Answer 15

A different version of a gene. Most plants and animals have two copies of a gene, one from each parent

Question 16

Define ‘genotype’

Answer 16

The alleles a person has eg. BB Bb bb

Question 17

Define ‘phenotype’

Answer 17

The physical characteristics expressed by an organism eg. Brown eyes

Question 18

Define ‘dominant’

Answer 18

Allele which is displayed in the phenotype even if only one copy is present

Question 19

Define ‘recessive’

Answer 19

Allele whose characteristic is only displayed in the phenotype if two copies are present

Question 20

Define ‘incomplete dominance’

Answer 20

When the trait from the dominant allele isn’t completely shown over the trait from the recessive allele = both alleles influence the phenotype
eg. Snapdragons have alleles for red (RR), white (rr) and pink (Rr)

Question 21

Define ‘homozygote’

Answer 21

An organism that carries two copies of the same allele for a certain characteristic eg. BB or bb

Question 22

Define ‘heterozygote’

Answer 22

An organism that carries two different alleles for a certain characteristic eg. Bb

Question 23

Define a ‘carrier’

Answer 23

If a recessive allele causes disease, a carrier is someone that has one recessive and one dominant allele (heterozygous)

Question 24

What is mono hybrid inheritance?

Answer 24

The inheritance of a single characteristic controlled by different alleles

Question 25

What is a genetic pedigree diagram?

Answer 25

Show an inherited trait in a group of related individuals

Question 26

When will a person have CF?

Answer 26

If they’re homozygous recessive for the cf allele

Question 27

What is cystic fibrosis caused by?

Answer 27

A mutation in the gene that codes for the CFTR protein (a channel protein)

Question 28

What does the CFTR channel protein do?

Answer 28

Transpires chloride ions out of cells and into mucus causing water to move in by osmosis making the mucus watery

Question 29

What happens to the mucus if there is a mutation in the CFTR channel protein?

Answer 29

Makes it less efficient at transporting chloride ions out of the cell so less water moves out by osmosis causing it to be sticky and thick