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AS-level Biology > AS past paper questions > Flashcards

AS past paper questions Flashcards

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
Explain why smoking toacco increases the risk of developing lung cancer
Tar contains carcinogens Causes mutations Uncontrolled cell division
26
Role of phloem sieve tubes
Transport sucrose from source to sink
27
Name of the tissue that forms the outer layer of the stem?
Epidermis
28
State the piece of equipment that can be used in the light microscope to work out the correct roportions of the tissue?
eyepiece graticule
29
What increases the risk of blood clots
nicotine
30
Why does cigarette smoking leads to decrease in the supply of oxygen to body tissues?
CO has greater affinity than oxygen with HB Carboxyhaemoglobin is formed Less Hb is available for O2 to bind
31
Differences between erythroblast and a mature RBC?
Mature RBC does not have nucleus RBC has biconcave shape RBC has no organelle
32
Semi-conservative replication?
- 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
How does penicilin acts on bacterial cells
- Attacks cell wall - so cell bursts - Prevents formation of cross links
34
Importance of telomerase?
Prevents loss of gene | Prevents degradation of the end of telomerase
35
Why is telomerase present in much higher quantities in stem cells and cancer cells than in other cell types
Mitosis occurs in both cell types
36
How is the spindle involved during the process of mitosis?
- Attatchment to centromere of each chromosome - Arranges chromosomes at the equator - Centromere division - Pulling chromatids towards the pole
37
Describe the effect of the mutation on the activity of enzyme and suggest an explanation
- 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
2 ways which co2 is transported in blood?
- CO2 dissolved in plasma | - Cabaminohaemoglobin
39
Role of elastic fibres in gas exchange system and in cardiovascular system?
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
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.
- 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
What is the role of memory cell?
Memory cells for secondary response Secondary immune response is faster than primary So higher concentration antibodies are produced
42
Role of ATP in mitosis?
For providing energy for the movement of centrioles to poles For spindle formation For the movement of chromosomes to the spindle equator
43
Describe and explain the sequence of events occuring in transpiration
- Water vapour enters air space - Diffusion of water vaour through stomata - Down the water potential gradient - Stomata opened
44
How can combination treatment for TB can help reduce the impact of antibiotic resistance?
- 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
Features that identifies the structure of bronchus and bronchiole
``` Bronchus: Irregular structure of cartilage - circular and big lumen - smooth muscle Bronchiole: no cartilage - Irrefular lumen shape ```
46
Explain the importance of clona expansion and the production of memory B-cells in providing protection for a person against an infectious disease
- Clonal expansion importance: - Cell growth - Old tissue replace - Cell repair Memory B cell matures to plasma cell that produce antibody
47
How does increase in co2 partial pressure produces the Bohr effect and state the benefit of this effect for the tissue
- 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
What is a component that increases the production and secretion of mucus from goblet cells
Tar
49
What is a component that causes a short-term increase in heart rate?
Nicotine
50
What is the function of mesophyll cell and its adaptation?
Photosynthesis - Has chloroplast - Large vacuole
51
Advantages of having infoldings for the movement of sucrose from mesophyll cells to phloem sieve tubes?
increase surface area More space for proton pumps Pumping protons from cytoplasm
52
What happens in a cell in preparation for cytokinesis?
The cell separates into 2 separate cells Increase in cytoplasm Formation of nuclear envelope Spindle disappears
53
Outline the role of stem cells in animal
Tissue repair Old cell replace Continue to divide To differentiate for formation of tissues
54
How does vaccine differs from antibiotics?
``` Vaccine: Not a treatment Effective against both bacteria and virus Stimulate immune response Provide long term immunity Not given as course ```
55
How does the structure of collagen is related to its functions within the mamalian cell?
``` 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
Describe the role of lysosome in intracellular digestion in bacteria
Fuses with pphagosome Add digestive enzyme ex) Lipase
57
Why is Haemoglobin globular
- Ball shaped/ Spherical - Water soluble - Hydrophillic R groups are outside
58
Why is polypeptide, Beta globin, is a polymer?
It is made of AA IT consists of a lot of monomers It is joined by peptide bond
59
Substitution mutation effects to Haemoglobin molecule?
Change in tertiary structure Change in quaternary structure Hb is less water soluble
60
What is the role of Hb in the transport of Co2?
Hb combines with Co2 Co2 reacts with terminal amine group To form carbaminohaemoglobin Each polypeptide can carry a molecule of co2
61
Outline one event that occurs during cytokinesis
Cytoplasm divides into 2
62
Explain the ways in which the structure of an artery is adapted to its function
Thick wall to withstand high bp Elastic tissue stretches to allow surges in bloodflow Smooth muscle maintains blood flow Collagen fibres bursting
63
Explain how tissue fluid is formed in the capillary network?
Higher pressure of blood at the start of capillary Filterfation of blood cause leakage out of plasma Glucose filtered out
64
Advantages and disadvantages of artificial passive immunity?
ADV: antibodies are provided to ppl immediately prevent diseases quicker DIS: short-term immunity No memory cells produced
65
Give example of natural passive immunity
From placenta | Breastfeeding

AS-level Biology (1 decks)

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