nucleotides🧬

Question 1

how does the structure of dna allow replication

Answer 1

• double stranded
• each strand acts as template
• h bonds easily broken between bases
• complementary base pairing
• purine only binds to pyramidine due to different sizes
• a to t, c to g

Question 2

role of mRNA

Answer 2

carries genetic info out of nucleus to ribosome for protein synthesis

Question 3

how many hydrogen bonds between a and t

how many hydrogen bonds between c and g

Answer 3

a and t= 2

c and g= 3

Question 4

why are there 64 combinations of codons but only 20 amino acids

Answer 4

• several triplets code for one amino acid
• some used for start or stop
• mutation may be silent

Question 5

why is dna replication semi conservative

Answer 5

• one new strand one old strand

- each strand acts as template to be copied

Question 6

why is complementary base pairing important for dna replication

Answer 6

• formation of identical dna
• reduces occurence of mutations
• allows formation of hydrogen bonds

Question 7

how is glucose well suited to its function

Answer 7

• easily broken down to release energy
• soluble so good for transport
• small molecule for transport/diffusion across cell membrane

Question 8

describe structural relationship between deoxyribose and other components of dna molecule

Answer 8

• phosphodiester bond to adjacent phosphate
• forms backbone
• bond with base and phosphate
• part of nucleotide

Question 9

how is dna analysis useful to taxonomists

Answer 9

• compare dna
• more similar dna=closer relationship
• used to put organisms into groups

Question 10

evidence used to classify organisms

Answer 10

• biochemical
• fossil record
• anatomy
• embryology

Question 11

why is dna evidence for a species from 1948 no longer useful

Answer 11

mutations have occures since then so different dna

Question 12

why can we study model organisms such as mice to learn about human dna

Answer 12

• similar genes
• similar metabolism
• same kingdom

Question 13

how does pairing of bases allow formation of identical DNA

Answer 13

• a to t ,c to g
• hydrogen bonding
• purine only to pyramidine due to different sizes