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AS-level Biology > AS past paper questions > Flashcards

AS past paper questions Flashcards

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1
Q

Structures that contains smooth muscle? (alveolus, bronchiole, bronchus, trachea)

A

Everything except for alveolus

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2
Q

Gene definition

A
  • sequence of nucleotides

- Gene can code for polypeptides

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3
Q

Advantage for using enzymes obtained from micro-organisms?

A
  • higher rate of reaction

- heat stable

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4
Q

Polysaccharide/monosacharride/macromolecule

  • Glucose
  • Maltase
  • Maltose
  • Starch
A

Glucose: monosaccharide & Macromolecule
Maltase: Macromolecule
Maltose: nothing
Starch: Polysaccharide & Macromolecule

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5
Q

One way cytokines are involved in immune response?

A

Stimulate Beta-lymphocyte response

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6
Q

Describe the shape

  • RBC:
  • Lymphocyte
  • Monocyte:
  • Neutriphil:
A
  • nucleus absent
  • nucleus present, large rounded nucleus
  • nucleus is kidney shaped
  • nucleus is lobed
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7
Q

Disease definition?

A
  • lack of physical well-being

- impaired function

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8
Q

what happens?:

  • S phase
  • Metaphase:
  • Anaphase:
A
  • DNA replication: produces 2 genetically identical daughter cell
  • chromosomes line on the equator
  • centromere splits: Daughter chromosomes moves to opposite poles
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9
Q

Why daughter cells are not identical immediately after cytokinesis?

A

Unequal sharing of cytoplasm

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10
Q

Suggest structural changes that occur when elongated cells develop into xylem vessel element and explain how these changes help xylem vessels to perform their function

A
  • Xylem transports water and mineral ions
  • end walls broken down
  • so tubes form
  • so uninterrupted flow
  • lignification
  • lignin strengthens vessels
  • cells become hollow
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11
Q

Explain how does binding of antibiotics to ribosome stops the growth of bacterial cell

A
  • mRNA unable to bind
  • ribosome subunits unable to come together
  • tRNA unable to enter ribosomes
  • translation prevented
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12
Q

what structure produces mRNA?

A

Nucleus

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13
Q

Describe hydrogen bonding

A

H is slightly positive charge
O is slightly negative charge
Each oxygen atom forms 2 hydrogen bonds

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14
Q

Explain the role of hydrogen bonding in maintaining secondary structure

A

It maintains structure of alpha-helixs and Beta-pleated sheet

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15
Q

Explain the role of hydrogen bonding in maintaining the tertiary structure of proteins

A

Helps to stabilise between R groups with amine and carboxyl group
Helps to maintain globular structure

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16
Q

Outline the importance of water as a solvent in plants

A

Dissolves ions and polar molecules
Trnasports dissolved substances in xylem
Storage of solutes

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17
Q

What is the role of carbonic anhydrase in the transport of CO2

A

It catalyses the reaction between water and co2 in RBC to form carbonic acid, which dissociates to form HCO3-
HCO3- moves into plasma
Activity of enzyme maintains steep concentration gradient for diffusion of co2 into RBC

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18
Q

Determine the factors that determine the globa distribution of malaria

A

Tropical regions
Anopheles only live in humid conditions
warm temperature for growth of parasite
In countries where prevention measures are not implemented
immunity to malaria in human population(limits distribution)

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19
Q

Outline the role of acid hydrolases in lysosome

A

break down bacteria
catalyse hydrolysis
Break down organelles

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20
Q

How does having very few organelles is an adaptation of the sieve tube element to its function

A

It reduces resistance to flow through sieve tube

Less space is taken up so increased volume of sap

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21
Q

Role of SAN?

A

Sends out electrical impulse to atria

Spreads across the atria

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22
Q

Immune response definition

A

Activation of lymphocytes

Due to non-self antigen

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23
Q

Advantages of using monoclonal antiboeis in the treatment of diseases such as myasthenia gravis

A

Very specific treatment
Binds to antigen on cell surface
Monoclonal antibodies are not recognised as foreign

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24
Q

Role of DNA polymerase in the replication of DNA

A

Joins a nucleotide to extending strand
Allows complementary base pairing
Forms phosphodiester bonds

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25
Q

Explain why smoking toacco increases the risk of developing lung cancer

A

Tar contains carcinogens
Causes mutations
Uncontrolled cell division

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26
Q

Role of phloem sieve tubes

A

Transport sucrose from source to sink

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27
Q

Name of the tissue that forms the outer layer of the stem?

A

Epidermis

28
Q

State the piece of equipment that can be used in the light microscope to work out the correct roportions of the tissue?

A

eyepiece graticule

29
Q

What increases the risk of blood clots

A

nicotine

30
Q

Why does cigarette smoking leads to decrease in the supply of oxygen to body tissues?

A

CO has greater affinity than oxygen with HB
Carboxyhaemoglobin is formed
Less Hb is available for O2 to bind

31
Q

Differences between erythroblast and a mature RBC?

A

Mature RBC does not have nucleus
RBC has biconcave shape
RBC has no organelle

32
Q

Semi-conservative replication?

A
  • DNA unwinds
  • Hydrogen bonds break between bases
  • Both strands are used as templates
  • Free activated DNA nucleotides are attracted to their complementary bases
  • Each newly formed molecule contains one original and one newly synthesized one
33
Q

How does penicilin acts on bacterial cells

A
  • Attacks cell wall
  • so cell bursts
  • Prevents formation of cross links
34
Q

Importance of telomerase?

A

Prevents loss of gene

Prevents degradation of the end of telomerase

35
Q

Why is telomerase present in much higher quantities in stem cells and cancer cells than in other cell types

A

Mitosis occurs in both cell types

36
Q

How is the spindle involved during the process of mitosis?

A
  • Attatchment to centromere of each chromosome
  • Arranges chromosomes at the equator
  • Centromere division
  • Pulling chromatids towards the pole
37
Q

Describe the effect of the mutation on the activity of enzyme and suggest an explanation

A
  • Rate of reaction is lower at all substrate concentrations
  • Greater difference as substrate concentration increases
  • It is less efficient
  • Active site is still binding substrate
  • Enzyme has lower affinity for substrate
38
Q

2 ways which co2 is transported in blood?

A
  • CO2 dissolved in plasma

- Cabaminohaemoglobin

39
Q

Role of elastic fibres in gas exchange system and in cardiovascular system?

A

For stretching to not break when there is high blood pressure
It stretches to prevent bursting
Allows trachea to expand
Arteries stretch as volume increases

40
Q

Describe the events that occur in the body after the macrophage has engulfed the bacteria until the productino of antibodies in response to the BCG vaccine.

A
  • Bacteria fuse with lysosome and this releases hydrolytic enzymes
  • And, macrophage becomes APC
  • Then, b-lymphocytes binds to antigen on cell surface membrane (antigen recognition)
  • This is clonal selection
  • Then, clonal expansion occurs, producing B-lymphocytes
  • B lymphocytes mature to plasma cells and secretes antibodies
41
Q

What is the role of memory cell?

A

Memory cells for secondary response
Secondary immune response is faster than primary
So higher concentration antibodies are produced

42
Q

Role of ATP in mitosis?

A

For providing energy for the movement of centrioles to poles
For spindle formation
For the movement of chromosomes to the spindle equator

43
Q

Describe and explain the sequence of events occuring in transpiration

A
  • Water vapour enters air space
  • Diffusion of water vaour through stomata
  • Down the water potential gradient
  • Stomata opened
44
Q

How can combination treatment for TB can help reduce the impact of antibiotic resistance?

A
  • In combination treatment, antibiotics act at different targets
  • Combination treatment eliminate bacteria more quickly
  • If one type of antibiotic has resistance, other antibiotic can be used
45
Q

Features that identifies the structure of bronchus and bronchiole

A 
Bronchus: Irregular structure of cartilage
- circular and big lumen 
- smooth muscle
Bronchiole: no cartilage
- Irrefular lumen shape
46
Q

Explain the importance of clona expansion and the production of memory B-cells in providing protection for a person against an infectious disease

A
  • Clonal expansion importance:
  • Cell growth
  • Old tissue replace
  • Cell repair
    Memory B cell matures to plasma cell that produce antibody
47
Q

How does increase in co2 partial pressure produces the Bohr effect and state the benefit of this effect for the tissue

A
  • Actively respiring tissue = more co2
  • Increase in formation of carbonic acid
  • More hydrogen ions bind to Hb
  • Causes more o2 to be unloaded
  • Haemoblogin affinity for O2 decreases.
48
Q

What is a component that increases the production and secretion of mucus from goblet cells

A

Tar

49
Q

What is a component that causes a short-term increase in heart rate?

A

Nicotine

50
Q

What is the function of mesophyll cell and its adaptation?

A

Photosynthesis

  • Has chloroplast
  • Large vacuole
51
Q

Advantages of having infoldings for the movement of sucrose from mesophyll cells to phloem sieve tubes?

A

increase surface area
More space for proton pumps
Pumping protons from cytoplasm

52
Q

What happens in a cell in preparation for cytokinesis?

A

The cell separates into 2 separate cells
Increase in cytoplasm
Formation of nuclear envelope
Spindle disappears

53
Q

Outline the role of stem cells in animal

A

Tissue repair
Old cell replace
Continue to divide
To differentiate for formation of tissues

54
Q

How does vaccine differs from antibiotics?

A 
Vaccine:
Not a treatment
Effective against both bacteria and virus
Stimulate immune response
Provide long term immunity
Not given as course
55
Q

How does the structure of collagen is related to its functions within the mamalian cell?

A 
Collagen has high tensile strength
In walls of arteries/veins
Triple helix has many hydrogen bonds between polypeptides
Collagen molecules form fibres
Strong covalent links between molecules.
56
Q

Describe the role of lysosome in intracellular digestion in bacteria

A

Fuses with pphagosome
Add digestive enzyme
ex) Lipase

57
Q

Why is Haemoglobin globular

A
  • Ball shaped/ Spherical
  • Water soluble
  • Hydrophillic R groups are outside
58
Q

Why is polypeptide, Beta globin, is a polymer?

A

It is made of AA
IT consists of a lot of monomers
It is joined by peptide bond

59
Q

Substitution mutation effects to Haemoglobin molecule?

A

Change in tertiary structure
Change in quaternary structure
Hb is less water soluble

60
Q

What is the role of Hb in the transport of Co2?

A

Hb combines with Co2
Co2 reacts with terminal amine group
To form carbaminohaemoglobin
Each polypeptide can carry a molecule of co2

61
Q

Outline one event that occurs during cytokinesis

A

Cytoplasm divides into 2

62
Q

Explain the ways in which the structure of an artery is adapted to its function

A

Thick wall to withstand high bp
Elastic tissue stretches to allow surges in bloodflow
Smooth muscle maintains blood flow
Collagen fibres bursting

63
Q

Explain how tissue fluid is formed in the capillary network?

A

Higher pressure of blood at the start of capillary
Filterfation of blood
cause leakage out of plasma
Glucose filtered out

64
Q

Advantages and disadvantages of artificial passive immunity?

A

ADV: antibodies are provided to ppl immediately
prevent diseases quicker

DIS: short-term immunity
No memory cells produced

65
Q

Give example of natural passive immunity

A

From placenta

Breastfeeding

AS-level Biology (1 decks)

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