Unit 1

Question 1

Name the 4 bases in DNA

Answer 1

Adenine, guanine, thymine, cytosine

Question 2

How are the bases paired

Answer 2

(A,T) (C,G)

Question 3

What is the shape of a DNA molecule

Answer 3

DNA molecule consists of 2 strands that wind around one another to form a shape as a double helix

Question 4

What are nucleotides in a chain joined together by

Answer 4

Sugar-phosphate bond

Question 5

Why are nucleotides in a chain joined together by a sugar-phosphate bond

Answer 5

To make long chains of nucleotides- called polynucleotides

Question 6

What are polynucleotides joined together to the bases with

Answer 6

Hydrogen bonds

Question 7

Why is the double helix described as having two anti-parallel chains of nucleotides

Answer 7

One side goes from 5’ to 3’ and the opposite side goes from 3’ to 5’

Question 8

What is DNA composed by

Answer 8

Two polynucleotide chains

Question 9

What does nucleotides consist of

Answer 9

A sugar-phosphate and base

Question 10

Why do nucleotides bond

Answer 10

To form a sugar-phosphate back bone

Question 11

What are the nucleic acid bases paired by

Answer 11

Hydrogen bonding in the centre to form a double helix

Question 12

What does a nucleus of a cell contain

Answer 12

Chromosomes, which are composed of genes made of DNA

Question 13

What does DNA Carry

Answer 13

Genetic info for making protein

Question 14

What Is required in a polymerase chain reaction (PCR)

Answer 14

DNA polymerase, template strand and prime

Question 15

Stage of aerobic respiration, it’s site and an event which occurs during that stage

Answer 15

Citric acid cycle, matrix of mitochondrion, carbon dioxide is released

Question 16

Name the molecules in an RNA nucleotide

Answer 16

deoxyribose in DNA attached to a phosphate group and a nitrogen-containing base.

Question 17

Name the type of bond on the backbone of the RNA molecule

Answer 17

Phosphodiester bonds

Question 18

Describe 3 differences between RNA and DNA molecules

Answer 18

RNA is single stranded while DNA is double stranded, RNA contains uracil while DNA contains thymine, RNA has the sugar ribose while DNA has the sugar deoxyribose

Question 19

State what mRNA is and describe its role

Answer 19

mRNA is a single-stranded molecule that carries genetic code from DNA in a cell’s nucleus to ribosomes, the cell’s protein-making machinery.

Question 20

State what tRNA is and describe its role

Answer 20

(tRNA) is a type of RNA molecule that helps decode a messenger RNA (mRNA) sequence into a protein

Question 21

State the location of transcription

Answer 21

In the nucleus

Question 22

Describe the process of transcription

Answer 22

Transcription is the process by which the information in a strand of DNA is copied into a new molecule of messenger RNA (mRNA).

Question 23

What are metabolic pathways

Answer 23

Metabolic pathways are integrated and controlled pathways of enzyme catalysed reactions within a cell

Question 24

What can metabolic pathways have

Answer 24

Reversible steps, irreversible steps and alternative routes

Question 25

Reactions in metabolic pathways can be

Answer 25

Anabolic or catabolic

Question 26

What do anabolic reactions do

Answer 26

They build up large molecules from smaller molecules and require energy

Question 27

What do catabolic reactions do

Answer 27

They breakdown large molecules into smaller molecules and release energy

Question 28

What are protein pores, pumps and enzymes embedded in

Answer 28

Membranes

Question 29

What are metabolic pathways controlled by

Answer 29

The presence or absence of particular enzymes and the regulation of the rate of reaction of key enzymes

Question 30

When does induced fit occur

Answer 30

When the active site changes shape to better fit the substrate after the substrate binds

Question 31

What do competitive enzymes bind to

Answer 31

The active site

Question 32

Why do competitive inhibitors bind to the active site

Answer 32

To prevent the substrate from binding

Question 33

What is the cell membrane

Answer 33

It is the boundary that separates the internal contents of the cell from its external surroundings

Question 34

What does the membrane do

Answer 34

The membrane regulates the flow of materials into and out the cell

Question 35

What are cell organelles bounded by

Answer 35

Membranes

Question 36

Meaning of catabolic pathways

Answer 36

Catabolic pathways are those that generate energy by breaking down larger molecules.

Question 37

The meaning of anabolic pathways

Answer 37

Anabolic pathways are those that require energy to synthesize larger molecules.

Question 38

Give example of catabolic reactions

Answer 38

An example of a catabolic reaction is the process of food digestion

Question 39

Example of anabolic reactions

Answer 39

An example of an anabolic reaction is the synthesis of glycogen from glucose

Question 40

Give example of a metabolic reactions which is reversible

Answer 40

Glycolysis results in the breakdown of glucose, but several reactions in the glycolysis pathway are reversible and participate in the re-synthesis of glucose

Question 41

Give an example of an alternative route for a metabolic pathway

Answer 41

Sorbitol

Question 42

What do membranes form surfaces and compartments for metabolic pathways

Answer 42

To localise metabolism

Question 43

Describe the functions of membrane proteins to include protein pores, pumps and enzymes

Answer 43

Transport proteins, enzymes, receptors, recognition proteins and joining proteins.

Question 44

Why enzymes speed up chemical reactions by lowering the activation energy

Answer 44

Enzymes generally lower activation energy by reducing the energy needed for reactants to come together and react.

Question 45

Why the induced fit model of enzyme action in terms of enzyme shape and binding the active site

Answer 45

The induced fit model states an substrate binds to an active site and both change shape slightly, creating an ideal fit for catalysis.

Question 46

What’s the effect of increasing substrate concentration on enzyme activity

Answer 46

an increase in substrate concentration leads to an increase in the rate of an enzyme-catalyzed reaction.

Question 47

What’s the effect of increasing end product concentration on the rate of enzyme reaction

Answer 47

increase the rate of the reaction.

Question 48

What’s an example of enzymes that work in groups or multi enzyme complexes

Answer 48

the pyruvate dehydrogenase complex (PDC)

Question 49

State that enzymes activity can be controlled by inhibitors

Answer 49

By binding to enzymes' active sites, inhibitors reduce the compatibility of substrate and enzyme and this leads to the inhibition of Enzyme-Substrate complexes

Question 50

What is competitive inhibitors

Answer 50

The competitive inhibitor binds to the active site and prevents the substrate from binding there

Question 51

What is non competitive inhibitors

Answer 51

The noncompetitive inhibitor binds to a different site on the enzyme

Question 52

What is respiration

Answer 52

the act or process of breathing : the inhaling of oxygen and the exhaling of carbon dioxide. 2 :the process by which cells use oxygen to break down sugar and obtain energy

Question 53

The rate of respiration is

Answer 53

Higher with glucose than with lactose