Nucleotides and nucleic acids And Enzymes

Question 1

What is a nucleotide made from?

Answer 1

Pentose sugar, nitrogenous base and a phosphate group

Question 2

What are ATP and ADP and what are they used for?

Answer 2

Nucleotides used to store and transport energy in cells

Question 3

What are the 2 purines?

Answer 3

Adenine and Guanine

Question 4

What are the 3 pyrimidines?

Answer 4

Cytosine, Thymine and Uracil

Question 5

What base does uracil replace?

Answer 5

Thymine

Question 6

What is an RNA molecule made up of?

Answer 6

A single polypeptide chain

Question 7

How do you phosphorylate a nucleotide?

Answer 7

Add one or more phosphate to it

Question 8

What is ATP made from?

Answer 8

Adenine, ribose and 3 phosphates

Question 9

What is ADP made from?

Answer 9

Adenine, ribose and 2 phosphates

Question 10

How is energy in ATP/ADP released?

Answer 10

Bonds are broken

Question 11

What do nucleotides form when joined together?

Answer 11

Polynucleotides

Question 12

How is a phosphodiester bond formed?

Answer 12

Phosphate and sugart from different nucleotides form via a condensation recation

Question 13

What does a chain of polynucleotides form?

Answer 13

A sugar-phosphate backbone

Question 14

How do polynucleotides join?

Answer 14

Hydrogen bonds between bases

Question 15

How many hydrogen bonds does C and G have?

Answer 15

3

Question 16

How many hydrogen bonds does A and T have?

Answer 16

2

Question 17

What does DNA helicase do? (Step 1)

Answer 17

Breaks hydrogen bonds and unzips DNA into 2 stands

Question 18

How does the DNA sequence act as a template? (Step 2)

Answer 18

Free-floating nucleotides join exposed bases

Question 19

How are the new DNA strands joined together with the original strands? (Step 3)

Answer 19

DNA polymerase

Question 20

What is semi-conservative replication?

Answer 20

DNA replication where the final DNA molecule contains one original DNA strand and one new DNA strand

Question 21

What is a gene?

Answer 21

A sequence of DNA nucleotides that code for a polypeptide

Question 22

Where is mRNA made?

Answer 22

In the nucleus

Question 23

what does mRNA carry?

Answer 23

Genetic code

Question 24

Where is tRNA found?

Answer 24

Cytoplasm

Question 25

What is an anticodon?

Answer 25

Three bases on the end of a tRNA molecule opposite to the amino acid

Question 26

What does rRNA do?

Answer 26

Catalyses the formation of peptide bonds in amino acids

Question 27

What does degenerate mean?

Answer 27

A codon can be used more than once with other codons to produce a different amino acid

Question 28

What does the genetic code being universal mean?

Answer 28

The same base triplets code for the same amino acids in all living things

Question 29

Outline the stages of transcription.

Answer 29

1) RNA polymerase attaches to DNA at beginning of gene 2) hydrogen bonds break 3) RNA polymerase lines up free nucleotides alongside template 4) U replaces T in complementary base pairing 5) mRNA formed 6) hydrogen bonds reform once RNA polymerase has passed 7) mRNA leaves through nuclear paws and attaches to ribosomes

Question 30

Outline the stages of translation.

Answer 30

1) tRNA carries amino acids to a ribosome 2) TRA with anticodon complementary to start codon attaches to mRNA 3) second tRNA attaches to next codon 4) rRNA catalyses formation of peptide bonds 5) third tRNA Binds to next codon, and second tRNA MOVES AWAY 6) process continues 7) polypeptide chain moves away

Question 31

What are enzymes?

Answer 31

Biological catalysts that speed up reactions

Question 32

What does intracellular mean?

Answer 32

Within cells

Question 33

What does extracellular mean?

Answer 33

Outside of cells

Question 34

What is an example of an intracellular enzyme?

Answer 34

Catalase works inside cells to catalyse the breakdown of hydrogen peroxide

Question 35

What is an example of an extracellular enzyme?

Answer 35

Amylase catalyses the breakdown of starch into maltose in the mouth

Question 36

What type of protein are enzymes?

Answer 36

Globular

Question 37

Define the lock and key model.

Answer 37

The substrate fits into the enzyme in the same way that a key fits into a lock

Question 38

Defined the induced fit model

Answer 38

The enzyme alters the shape of its active site to fit the substrate more closely

Question 39

Which theory is better, lock and key or induced fit?

Answer 39

Induced fit

Question 40

What are the factors that affect enzyme activity?

Answer 40

• temperature • pH • enzyme concentration • substrate concentration

Question 41

How does temperature affect enzyme activity?

Answer 41

High temperatures means there’s more kinetic energy so there are more frequent collisions. If it gets too hot, the enzyme will denature

Question 42

How does pH affect enzyme activity?

Answer 42

Above and below the optimum pH can break ionic and hydrogen bonds

Question 43

How does enzyme concentration affect enzymes?

Answer 43

High concentration means more collisions

Question 44

How does substrate concentration affect enzymes?

Answer 44

High concentration means more collisions

Question 45

What a non-protein substance allows some enzymes to work

Answer 45

Cofactors

Question 46

What do inorganic cofactors do?

Answer 46

Only help the enzyme and the substrate to bind together

Question 47

What do organic cofactors do? What are they called?

Answer 47

Coenzymes that participate in the reaction and act as a second substrate

Question 48

What is an enzyme inhibitor?

Answer 48

Molecules that bind to the enzyme and stop it from functioning

Question 49

What is competitive inhibition?

Answer 49

They have a similar shape to the substrate and compete to bind to the active site

Question 50

What is non-competitive inhibition?

Answer 50

Molecules bind to the allosteric site and change the shape of the active site, so the substrate cannot bind

Question 51

What determines if an inhibitor can be reversed?

Answer 51

If it has a strong covalent bond, it cannot be reversed, if they have weaker hydrogen bonds, they can be reversed

Question 52

How do anti-viral drugs stop viruses?

Answer 52

Reverse transcript, inhibitors prevent replication of the viral DNA

Question 53

What is the metabolic pathway?

Answer 53

A series of connected metabolic reactions where the product of the first reaction takes part in the second reaction and so on

Question 54

What is product inhibition?

Answer 54

Where the enzyme is inhibited by the product they produce