Gene Expression

Question 1

what is gene expression?

Answer 1

• is the process by which a gene produces its product & the product carries out its functions

Question 2

what is transcription?

Answer 2

is the process of making a copy of the genetic information stored in a DNA strand into a complementary strand of mRNA.

Question 3

what is a Gene?

Answer 3

A section of DNA or chromosome that codes for a polypeptide

Question 4

what are the stages of transcription?

Answer 4

1. Hydrogen bonds between DNA bases break
2. only one DNA strand acts as a template
3. Free RNA nucleotides align by complementary base pairing
4. In RNA Uracil base pairs with adenine on DNA or in RNA Uracil is used in place of thymine
5. RNA polymerase joins adjacent RNA nucleotides
6. by phosphodiester bonds
7. Pre- mRNA is spliced to form mRNA OR Introns are removed to form mRNA.

Question 5

what is codon

Answer 5

a specific sequence of three adjacent bases on a strand of RNA that provides genetic code information for a particular amino acid

Question 6

what is anticodon?

Answer 6

group of three bases on a tRNA molecule that are complementary to an mRNA codon

Question 7

what is tRNA(transfer RNA)

Answer 7

type of RNA molecule that transfers amino acids to ribosomes during protein synthesis

Question 8

what is amino acid activation

Answer 8

the process of loading amino acid to tRNA using ATP.

Question 9

what is translation

Answer 9

the process by which mRNA is decoded and a polypeptide is produced

Question 10

what are the stages of translation

Answer 10

1. mRNA attaches to ribosomes
2. tRNA anticodons bind to complementary mRNA codons
3. tRNA brings a specific amino acid
4. Amino acids join by peptide bonds
5. Amino acids join together with the use of ATP
6. tRNA released after amino acid joined to polypeptide
7. the ribosome move along the mRNA to form the polypeptide

Question 11

Gene mutation

Answer 11

is the change in the base sequence of a gene. This happens during DNA replication

Question 12

what are three types of mutations?

Answer 12

• deletion mutation is a mutation in which one or more pairs of nucleotides a removed from a gene
• substitution mutation is a single base is replaced, potentially altering the gene product
• Insertion mutation is one or more nucleotides are added to a gene

Question 13

how mutation results in a non-functional protein and mutation in stop codon:

Answer 13

primary structure of the protein would alter which would change how the protein folds in the tertiary structure.
this results in a shorter polypeptide chain

Question 14

what is germline and somatic mutation?

Answer 14

-DNA alteration occurring in gametes that can be transmitted to offspring
- A mutation that occurs in the body cells. Cannot be inherited.