DNA and genetic diseases

Question 1

What is DNA an abbreviation for?

Answer 1

Deoxyribonucleic acid

Question 2

Name the components of a DNA nucleotide.

Answer 2

Deoxyribose
Phosphate
Nitrogenous organic base - guanine, cytosine, adenine or thymine

Question 3

Name the type of bond formed between complementary bases

Answer 3

Hydrogen bond

Question 4

Name the pyrimidine bases

Answer 4

Cytosine and Thymine

Question 5

Name the purine bases

Answer 5

Guanine and adenine

Question 6

How many rings structures are present in a purine base

Answer 6

Two

Question 7

How many ring structures are present in a pyrimidine base?

Answer 7

One

Question 8

How many ring structures are present in a pyrimidine base?

Answer 8

One

Question 9

Describe the shape of a DNA molecule

Answer 9

Double helix - two antiparallel polynucleotide chains held together by hydrogen bonds between specific complementary base pairs.

Question 10

The two polynucleotide strands in DNA are antiparallel. True or false

Answer 10

True

Question 11

Give the specific complementary base pairs found in DNA.

Answer 11

Guanine and cytosine
Thymine and adenine.

Question 12

Name the process involved in the replication of DNA

Answer 12

Semi-conservative replication

Question 13

What is the function of DNA helicase?

Answer 13

Breaks the hydrogen bonds between the complementary bases in the helix, unwinding the DNA and exposing unpaired bases.

Question 14

Describe the process of DNA replication

Answer 14

Unwinding of double helix
Breaking bonds between complementary bases
Catalysed by DNA helicase.

Diffusion of new DNA nucleotides to exposed bases on template strands and base pairing.
Hydrogen bonds form between complementary bases
Formation of bonds between adjacent nucleotides in the new strand of DNA.
Catalysed by DNA polymerase.

Question 15

Name the enzyme responsible for breaking the hydrogen bonds between the 2 strands of DNA?

Answer 15

DNA helicase

Question 16

Name the enzyme used to catalyse the production of bonds between adjacent nucleotides

Answer 16

DNA polymerase

Question 17

Give two differences between a DNA and RNA nucleotide.

Answer 17

DNA contains deoxyribose whereas RNA contains ribose.
DNA contains thymine whereas RNA contains uracil.

Question 18

How are the 2 strands of DNA that make up the double helix held together?

Answer 18

Hydrogen bonds between complementary nitrogenous bases

Question 19

What is meant by ‘semi conservative’ DNA replication?

Answer 19

Each new DNA molecule contains an original and new strand of DNA

Question 20

Describe the role of DNA helicase in transcription

Answer 20

DNA helicase breaks hydrogen bonds between the bases in the helix, unwinding the DNA and exposing unpaired bases.
RNA polymerase links to the template strand of

Question 21

Describe the role of RNA polymerase in transcription

Answer 21

DNA polymerase links to the template strand of DNA, inserting mRNA nucleotides one at a time, according to the rules of complementary base pairing and forming bonds between them.

Question 22

How many bases are needed to code for one amino acid on the DNA?

Answer 22

The code is 3 bases long (called a triplet)

Question 23

Give the name for three bases on the mRNA that code for one amino acid

Answer 23

Codon

Question 24

What is a stop sequence on the DNA?

Answer 24

Indicates the end of the gene. RNA polymerase leaves the DNA and transcription stops

Question 25

How many attachment sites for tRNA are present on the ribosome?

Answer 25

Two

Question 26

How many sub-units are there in a ribosome?

Answer 26

Two

Question 27

Which sub-unit does mRNA attach to on the ribosome?

Answer 27

Small sub unit

Question 28

Which sub unit does tRNA attach to on the ribosome?

Answer 28

Large sub unit

Question 29

What doe tRNA molecules carry to the ribosome?

Answer 29

A specific amino acid

Question 30

Describe the process of translation.

Answer 30

Ribosome binds to the start codon on the mRNA. tRNA molecules bind to the ribosome through codon-anticodon interactions. A peptide bond forms between 2 amino acids. The ribosome moves along the mRNA one codon at a time. This continues until the stop codon is reached

Question 31

The genetic ode is linear and non-overlapping. What does this mean?

Answer 31

Linear - one continuous sequence Non-overlapping - bases are read in sequence.

Question 32

The genetic code is degenerate. What does this mean?

Answer 32

Several triplets can code for the same amino acid.

Question 33

The genetic code is universal and unambiguous. What does this mean?

Answer 33

The genetic code is the same in all living organism's

Question 34

Cystic fibrosis is an inherited disease. What does this mean?

Answer 34

Alleles pass from one generation to the next. It caused by a mutation on the DNA

Question 35

Some inherited diseases are recessive. What does this mean?

Answer 35

Individual must be homozygous for this condition. Must have inherited recessive alleles from both parents

Question 36

Polydactyly is a dominant condition. What does this mean?

Answer 36

An individual only needs one dominant allele to show polydactyly