UNIT 1 - KA3

Question 1

What does gene expression involve

Answer 1

Gene expression involves the transcription and translation of DNA sequences

Question 2

What are the three types of RNA involved in transcription and translation

Answer 2

mRNA - messenger RNA (mRNA)
tRNA - transfer RNA (tRNA)
rRNA - ribosomal RNA (rRNA)

Question 3

What is the full name for RNA

Answer 3

Riobnucleic acid

Question 4

What type of molecule is RNA

Answer 4

RNA is single stranded

Question 5

What is in an RNA nucleotide

Answer 5

Phosphate , ribose sugar , base

Question 6

What are the bases of RNA

Answer 6

A - Adenine
U - Uracil
G - Guanine
C - Cytosine

Question 7

What are the 3 main differences between DNA AND RNA

Answer 7

• RNA is single stranded, it’s complementary base partner of adenine is uracil and it had ribose sugar in the nucleotides
• DNA is a double stranded molecule, its complementary base partner of adenine is Thymine and it has deoxyribose sugar in the nucleotides

Question 8

What is the job of mRNA and where is it found

Answer 8

mRNA- carries complementary copy of the DNA code from the nucleus to the ribosome in the cytoplasm. It is found in

Question 9

What is the job if tRNA and where is it found

Answer 9

tRNA - carries its specific amino acid to the ribosome in the cytoplasm. It is found in

Question 10

What is the job of rRNA and where is it found

Answer 10

rRNA - forms the ribosome along with proteins in the cytoplasm. It is found in

Question 11

Where is mRNA transcribed from

Answer 11

mRNA is transcribed from DNA in the nucleus

Question 12

What does mRNA do - from and to

Answer 12

mRNA carried copy of the DNA code from the nucleus to the ribosome

Question 13

What is each triplet of bases on an mRNA called

Answer 13

Each triplet of bases on an mRNA is called a CODON

Question 14

What is the enzyme of transcription

Answer 14

RNA polymerase

Question 15

What is the first step of transcription (what is unwound and broken)

Answer 15

1- RNA polymerase moves along DNA unwinding the double helix + breaking the hydrogen bonds between the bases of DNA coding for the gene to be expressed

Question 16

What is the second step of transcription (what moves towards exposed bases and what does it form)

Answer 16

2- Free RNA nucleotides move towards the exposed bases of one strand and form complementary base pairs.

Uracil pairs with adenine and guanine with cytosine

Question 17

What is the third stage of transcription (what does RNA polymerase synthesise)

Answer 17

3- RNA polymerase synthesises a primary transcript of mRNA from RNA nucleotides by base pairing

Question 18

Modification of primary transcript - what is an INTRON

Answer 18

INTRON (IN THE BIN) - An intron is a non coding region of DNA. They do not code for the polypeptide chain and must be removed from the primary transcript before translation.

Question 19

Modification of primary transcript - what is an EXON

Answer 19

EXON - An exon is a coding region of DNA. All of the exons must be joined together to make the mature mRNA transcript

Question 20

What is RNA splicing

Answer 20

RNA splicing forms a mature mRNA transcript. The introns of the primary transcript are non coding regions and are removed. The exons are coding regions and are joined together to form the mature transcript.

Question 21

What happens to the order of exons during splicing

Answer 21

The order of exons during splicing is unchanged

Question 22

What type of RNA does translation involve

Answer 22

tRNA - transfer RNA

Question 23

How big is tRNA

Answer 23

This is a smaller molecule than mRNA

Question 24

What does tRNA do

Answer 24

The tRNAs job is to carry its specific Amino Acid to the ribosome for translation

Question 25

Draw a diagram of tRNA labels

Answer 25

Check jotter

Question 26

Where does translation take place

Answer 26

Translation takes place in the cytoplasm

Question 27

What happens before translation

Answer 27

mRNA carries a copy of the DNA code from the nucleus to the ribosome

Question 28

What do tRNA molecules do at the start of translation (1st stage of translation)

Answer 28

tRNA molecules pick of their specific amino acid and take them to the ribosome

Question 29

Where does translation begin and end (2nd stage of translation)

Answer 29

Translation begins at a start codon and ends at a stop codon on the mRNA

Question 30

How do anti codons bond to codons and what do they translate the genetic code into (3rd stage of translation)

Answer 30

Anticodons bond to codons by complementary base pairing translating the genetic code into a sequence of amino acids

Question 31

Which type of bonds join amino acids (4th stage of translation)

Answer 31

Peptide bonds join the amino acids together

Question 32

What happens to the tRNA as the polypeptide is formed (5th stage of translation)

Answer 32

Each tRNA leaves the ribosome as the polypeptide is formed

Question 33

What happens in alternative RNA splicing

Answer 33

In alternative RNA splicing, different mature mRNA transcripts are produced from the same primary transcript depending on which exons are retained. The order of the exons is unchanged during splicing

Question 34

What are polypeptide chains made of

Answer 34

Amino acids which are linked by peptide bonds

Question 35

Polypeptide chains fold to form what shape?

Answer 35

Polypeptide chains fold to form the 3-D shape of a protein held together by hydrogen bonds and other interactions between individual amino acids

Question 36

What do proteins have a large variety of

Answer 36

Proteins have a large variety of shapes which determines their functions

Question 37

What is phenotype determined by

Answer 37

Phenotype is determined by proteins produced as a result of gene expression

Question 38

What factors can influence phenotype

Answer 38

Environmental factors can also influence phenotype such as skin cancer

Question 39

What are some functions of protein

Answer 39

Structural , enzymes , antibodies , hormones

Question 40

How much of the genes In a cell are expressed

Answer 40

Only a fraction of the genes in a cell are expressed

Question 41

What is an anticodon

Answer 41

Triplet of bases which pairs with CODON of mRNA strand