11: DNA & RNA structure and function

Question 1

Mendel’s 3 findings on genetics

Answer 1

1. genes are on chromosomes
2. gene mutations cause metabolic errors
3. DNA is made up of nucleotides

Question 2

What are the 4 nucleotides that make DNA?

Answer 2

1. Adenine
2. Cytosine
3. Guanine
4. Thymine

Question 3

How is a nucleotide of DNA structured?

Answer 3

• 1 base
• 1 phosphate group
• 1 sugar deoxyribose

Question 4

Chargaff’s Rules

Answer 4

nucleotide bases are found in specific proportions

• amount of A, C, G, T differs btwn species
• amount of A = T amount of C = G

Question 5

Rosalind Franklin findings. What did she use?

Answer 5

• used x-ray crystallography
• DNA is helical

Question 6

Watson & Crick findings

Answer 6

• The sugar and phosphate groups are bonded (ladder)
• Bases are joined by hydrogen bonds (rungs of ladder)
• complementary bases (A&T, C&G)

Question 7

DNA Replication

Answer 7

• original strands serve as templates
• 1 original strand is present in new helix

Question 8

Origins of Replication

Answer 8

where DNA replication is initiated along the DNA strand

Question 9

Replication Bubbles

Answer 9

splitting of DNA helix in origin of replication site

Question 10

RNA structure

Answer 10

• Adenosine
• Cytosine
• Guanine
• Uracil (sugar ribose)

Question 11

m(RNA)

what does it carry? where is it made?

Answer 11

• messenger RNA
• produced in nucleus through transcription
• carries genetic info from DNA to cytosol

Question 12

t(RNA)

what does it do? how many types?

Answer 12

• transfer RNA
• carries amino acids to protein synth. site
• 20 different types for 20 different amino acids
• amino acid on one end and an anticodon on the other end

Question 13

r(RNA)

what do they do?

Answer 13

• ribosomal RNA
• 2 r(RNA) join with proteins in cytosol to form subunits of ribosomes

Question 14

How does DNA make protein?

Answer 14

genes in DNA contain instructions for amino acid sequence of a protein

Question 15

What happens if there is an error in a gene for an enzyme?

Answer 15

• becomes non-functional
• biochemical pathway may be affected
• can create inborn errorsin metabolism that lead to metabolic diseases

Question 16

What does the sequence of amino acid determine for a protein?

Answer 16

unique shape and function

Question 17

Transcription

Answer 17

synth of m(RNA) from template DNA

Question 18

Translation

Answer 18

m(RNA) directs the sequence of amino acids in the protein

Question 19

Triplet Code

Answer 19

info for amino acid sequence of a protein encoded within a gene

Question 20

Codons

where are they found? what do they provide?

Answer 20

• in m(RNA)
• how triplet code is transcribed
• provide redundant sequences for the placement of amino acids in a protein

Question 21

DNA Transcription

Answer 21

1. RNA polymerase binds to DNA promoter of a gene
2. DNA helix unwound
3. primary mRNA strand is formed
4. mRNA is complementary to DNA sequence

Question 22

Anticodons during Translation

Answer 22

• mature RNA moves to a ribosome
• sequence of codons dictates sequence of complimentary anticodons
• order of t(RNA) molecules determines order of amino acids

Question 23

3 phases of Translation

Answer 23

1. Initiation: small ribosomal subunit, large ribosomal subunit, the mRNA, and a tRNA carrying a methionine bond to the mRNA to start transcription
2. Elongation: amino acid sequence is extended
3. Termination: when protein synth is done

Question 24

What does Gene Mutation do to the DNA?

Answer 24

changes the seqence of bases

Question 25

mutagens

Answer 25

• cause mutations
• i.e. radiation, chemicals

Question 26

Germ-line Mutations

Answer 26

inherited mutations

Question 27

Somatic Mutations

Answer 27

occurs after birth and can lead to cancer

Question 28

Point Mutation

Answer 28

change of single DNA nucleotide (A, C, G, T)

Question 29

Polymerase Chain Reaction

Answer 29

technique that amplifies DNA synthesis

• need primer