[🧫] Nucleic Acids and Protein Synthesis

Question 1

Define

gene mutation

Answer 1

a change in one or more nucleotide bases in DNA that could result in a change in genotype which may be inherited

Question 2

Define

autosome

Answer 2

a chromosome that is not a sex chromosome

Question 3

Define

homologous chromosomes

Answer 3

a pair of chromosomes, one maternal and the other paternal, that have the same gene loci and therefore determine the same features.

they are not necessarily identical; they may have different alleles; they are capable of pairing during meiosis

Question 4

Define

codon

Answer 4

a sequence of three adjacent nucleotides in mRNA that codes for one amino acid

Question 5

Define

anti-codon

Answer 5

a sequence of three adjacent nucleotides in tRNA that is complementary to a particular codon on mRNA

Question 6

Define

chromosome

Answer 6

a thread-like structure made up of histone proteins and DNA by which hereditary information is physically passed from generation to generation

Question 7

Define

alleles

Answer 7

alternative forms of a gene with different base sequences, and therefore different codes

Question 8

Define

diploid

Answer 8

a cell or nucleus containing pairs of homologous chromosomes

Question 9

Define

haploid

Answer 9

a cell or nucleus containing single, unpaired chromosomes

Question 10

Define

nucleotides

Answer 10

complex chemicals made up of an organic base, a sugar and a phosphate group; the basic units of which DNA and RNA are made up of

Question 11

Define

DNA helicase

Answer 11

• enzyme
• break H-bonds between bases, separating the two nucleotide strands to expose the bases in DNA replication and protein transcription

Question 12

Define

RNA polymerase

Answer 12

• enzyme
• joins RNA nucleotides together to form mRNA during transcription

Question 13

Define

transcription

1st stage of protein synthesis

Answer 13

the formation of mRNA molecules from the DNA that makes up a particular gene

Question 14

Define

gene

Answer 14

a sequence of nucleotides that forms part of a DNA molecule

Question 15

The importance of hydrogen bonding between the two strands of DNA in DNA replication

Nucleic Acids and Protein Synthesis

Answer 15

• there are many hydrogen bonds between the two strands, ensuring that the strands are not easily separated and are long-lasting
• hydrogen bonds are weak enough to be broken easily so that strands can be separated during DNA replication
• hydrogen bonds only form between complementary bases so there is faithful replication

Question 16

Significance of DNA being very stable

Nucleic Acids and Protein Synthesis

Answer 16

• the DNA sequence will not spontaneously change so the proteins and DNA copies produced from DNA will always be functional
• maintains all genetic information to be passed on to daughter cells

Question 17

Significance of mRNA being highly labile (unstable)

Nucleic Acids and Protein Synthesis

Answer 17

• protein synthesis will stop when mRNA is broken down
• nucleotides can be reused for other mRNA

Question 18

When does DNA transcription take place?

Nucleic Acids and Protein Synthesis

Answer 18

throughout Interphase

Question 19

When does DNA replication take place?

Answer 19

late Interphase / S-phase

Question 20

Role of ribosome in translation

Nucleic Acids and Protein Synthesis

Answer 20

• attached 2 codons to itself at a time
• catalyses the formation of peptide bonds
• moves along the mRNA one codon at a time
• site of attachment of mRNA to anti-codons of tRNA