KK 1 Nucleic acids and Proteins

Question 1

what is The cell theory?

Answer 1

1. All organisms are composed of cells
2. all cells come from pre-existing cells
3. the cell is the smallest living organisational unit

Question 2

What are Biomacromolecules

Answer 2

large organic molecules made of smaller subunits that are bonded together, componds formed in this way are called polymers

Question 3

What are nucleic acids

Answer 3

the organic biomolecules that store and transmit inherited characteristics of organisms and encode instruction for the synthesis of proteins

Question 4

Types of nucleic acids

Answer 4

Deoxyribonucleic acid, Ribonucleic acid

Question 5

Purine bases (2 ring structure)

Answer 5

Adenine and Guanine

Question 6

Pyrimidine bases (1 ring structure)

Answer 6

Thymine, uracil and cytosine

Question 7

function of messenger RNA (mRNA)

Answer 7

carries the genetic code to the ribosome in the cytosol

Question 8

function of Ribosomal RNA (rRNA)

Answer 8

reading the order of amino acids and linking amino acids together

Question 9

Function of Transfer RNA (tRNA)

Answer 9

transfers amino acids in the cytosol to the ribosome to form a polypeptide chain

Question 10

Factors of the genetic code

Answer 10

Universal - same in all organisms
Degenerate - More than one codon codes for the same amino acid

Question 11

what is pre-mRNA

Answer 11

mRNA that has not undergone post-transcriptional modification, still contains introns

Question 12

What is a Methyl cap

Answer 12

1. Attached to the 5’ end
2. altered guanine base,
3. protects the molecule from enzyme degradation
4. helps attach mRNA to the ribosome

Question 13

What is a Poly-A tail

Answer 13

1. Attached to the 3’ end
2. up to 250 adenine nucleotides added
3. facilitated transport of mRNA from the nucleus
4. protects molecules from enzyme degradation

Question 14

switched on genes are considered

Answer 14

Induced

Question 15

Switched off genes are considered

Answer 15

repressed

Question 16

Constitutive genes are

Answer 16

always switched on and are transcribed continually

Question 17

function of regulatory genes

Answer 17

control the expression of structural genes

Question 18

trp operon definition

Answer 18

a repressible prokaryotic model of how transcription factors regulate gene expression

Question 19

how can trp operon be regulated

Answer 19

Repression - switches transcription off
Attenuation - slows transcription down

Question 20

what happens when tryptophan is present - trp operon switched off

Answer 20

tryptophan binds to the repressor protein causing a change in its shape meaning RNA polymerase is unable to bind to the promoter and transcription cannot occur

Question 21

What happens when tryptophan is not present - trp operon switched on

Answer 21

repressor is inactive and cannot bind to the operator, RNA polymerase is able to bind to the promoter and begin transcription

Question 22

what happens when transcription has begun with high tryptophan

Answer 22

Attenuation, this prevents completion of transcription, RNA polymerase stops transcribing early making a non-functional protein

Question 23

How does a terminator hairpin occur

Answer 23

in a high tryptophan environment, the ribosome will rapidly translate the leader sequence creating a terminator hairpin this SLOWS gene expression

Question 24

How does an anti-terminator hairpin occur

Answer 24

In a low tryptophan environment, the ribosome will slowly translate the leader sequence, and gene expression occurs

Question 25

amino acid structure examples

Answer 25

Amine group, carboxyl group, Variable R group

Question 26

what happens in condensation reactions

Answer 26

amino acids are joined by peptide bonds, an OH from the carboxyl group and a H from the amine group is released as a water molecule

Question 27

Primary structure

Answer 27

the first form of a protein, a specific linear sequence of amino acids

Question 28

Secondary structure

Answer 28

the polypeptide chain is folded and or coiled due to hydrogen bonds forming between amino acids

Question 29

Tertiary structure

Answer 29

The polypeptide chain folds into a 3D structure, may be the final structure for some proteins

Question 30

Quaternary structre

Answer 30

when two or more polypeptide chains join together to create a single functional protein

Question 31

what is the proteome

Answer 31

the complete array of proteins produced by a single cell or organism in a particular environment

Question 32

the role of the Rough ER in secretory pathways

Answer 32

1. transports proteins within the cell
2. folding of primary polypeptide chains

Question 33

The role of the Golgi apparatus in secretory pathways

Answer 33

Modification and packaging of proteins

Question 34

the role of vesicles in secretory pathwyas

Answer 34

moves to plasma membrane where it fuses and releases proteins via exocytosis