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A-Level OCR Biology > Module 4 - Communicable diseases > Flashcards

Module 4 - Communicable diseases Flashcards

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1
Q

What happens if DNA damage is discovered at the G2 checkpoint

A

The cell cycle is halted and the cell tries to repair the DNA

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2
Q

which stage is where chromosomes line up at the equator of the cell

A

Metaphase

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3
Q

Explain how scientists are able to estimate the age of extinct organisms

A

By looking at fossils

The deeper in the ground, the older the fossil

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4
Q

Explain how biological molecules can provide evidence that species have evolved

A

Biological molecules - look at DNA, the similarity shows evolutionary relationship
Look at amino acid sequences, if the sequence is similar then you know there is an evolutionary relationship

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5
Q

Explain the importance of sampling in measuring the biodiversity of a habitat.

A

Sampling provides an estimate of the number of species in an area as counting every individual is difficult and time consuming

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6
Q

Why is it important to take samples in fenced and unfenced areas

A

To compare the two areas

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7
Q

Explain the difference between species richness and species evenness and why both measurements are needed to assess biodiversity.

A

Species richness is the number of species in a habitat.
Species evenness is the number of individuals in each species.
The higher the biodiversity is associated with both species richness and species evenness.

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8
Q

Lupus is an autoimmune disease, what indicates on a blood test that lupus is confirmed

A

Presence of antibodies for the cell surface antigens of connective tissue

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9
Q

An individual bitten by a rabid dog can be treated by an injection of human rabies antibodies.
What type of immunity provides this treatment

A

Artificial passive

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10
Q

Coeliac disease is caused by an immune reaction to gliadins in a person’s digestive system, it causes inflammation
Some people who stop eating foods that contain gluten still occasionally experience the symptoms

What can you conclude about
the structure of the antibody that causes coeliac disease and what the antibody binds to when producing the symptoms of coeliac’s disease

A

Variable region of antibody is not specific

Antibody binds to T lymphocytes and the mast cell releases histamines which causes inflammation

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11
Q

Three methods of pathogen transmission between animal or plants are listed below
1. Direct contact
2. Vectors
3. Droplets
Which of the methods of pathogen transmission can apply to plants

A

Direct contact and vectors

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12
Q

Does the antibiotic resistance in bacteria evidence to support Darwin’s theory of evolution by natural selection?

A

yes

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13
Q

Which of the following antibodies increase the phagocytosis of pathogens

  1. Opsonins
  2. Agglutinins
  3. Anti Toxins
A

Opsonins and Agglutinins

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14
Q

Rheumatoid arthritis is a long term condition that causes pain, swelling and stiffness in the joints.
What explains why stem cells are a potential source of treatment for rheumatoid arthritis?

A

Stem cells allow regeneration of a variety of tissue types

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15
Q

The sweet potato is a plant that is a staple food in countries such as China. The sweet potato is susceptible to a group of viruses known as potyviruses.

It is difficult for the virus to enter the sweet potato.
Suggest a barrier that makes it difficult for potyviruses to enter the sweet potato

Suggest how the potyviruses enter the sweet potato cell

A

Cellulose cell wall

A wound

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16
Q

Explain what is meant by an autoimmune disease and suggest why members of the same family can be sufferers of autoimmune diseases

A

Autoimmune disease is when the immune system attacks your own body cells/tissue.
The genes can be passed down

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17
Q

What type of pathogen is for tuberculosis

A

Bacteria

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18
Q

What type of pathogen for potato late blight

A

Protist

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19
Q

What type of pathogen Is malaria

A

Protist

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20
Q

Outline the action of agglutinins

A

The pathogens clump together to stop pathogens from reproducing
as it helps phagocytes engulf multiple pathogens in one time

21
Q

What are the 5 steps to how a vaccine gives an individual immunity.

A

A vaccine is produced that is a safe form of an antigen
A small amount of vaccine is injected into blood of the individual to be vaccinated
Antigen binds to specific B lymphocyte
Clonal expansion and plasma cells are produced
Memory cells remember and secondary immune response occurs

22
Q

Antibodies are important biological molecules.

Describe how the structure of antibodies allows them to perform their function.

A

Antibodies have 2 light chains and 2 heavy chains
There is a variable region which allows binding to antigen, there are 2 variable regions allowing for more binding to occur.
The constant region allows recognition of phagocytes
Hinge region allows flexibility
The light and heavy regions are held together by disulphide bonds.

23
Q

Antibodies have a number of mechanisms of action. For example, agglutinins cause pathogens to be rendered inactive by clumping them together.

Outline the action of opsonins?

A

Increases the likelihood of phagocytosis, it binds to pathogens and phagocyte

24
Q

what formula is an estimate of the volume of a neutrophil

A

4/3 pie r ^3

25
Q

State two ways in which frankincense contributes to defending the tree from pathogens

A

Prevents pathogens entering wound

aromatic compound is antibacterial

26
Q

What type of disease is rheumatoid arthritis?

A

Autoimmune

27
Q

Explain how traditional remedies such as the use of frankincense provide a strong argument for conservation of biodiversity

A

many plants produce molecules that may have medical benefits

28
Q

name two different types of T lymphocytes and describe their roles in the immune response

A

T helper cells which release interleukins

T memory cells allow a secondary immune response

29
Q

Explain why it is not possible to protect against the different pathogens using only one vaccine.

A

different pathogens have different antigens
antigens have specific shape
shape of antibody must be complementary to the specific antigen

30
Q

Outline the processes that lead to the production of antibodies against an unfamiliar bacterium.

A

B cells carry antibody complementary to an antigen
The B cell is activated and divides by mitosis
It differentiates into plasma cells which secret antibodies specific to antigen

31
Q

Explain how helper T cells act to speed up the process of making antibodies

A

T helper cells stimulated by antigen presenting cells release interleukin which stimulated B cell for mitosis

32
Q

State the role of cytokines

A

attract phagocytes

33
Q

The concept of molecules with complementary shapes can be used to explain many processes in living things.
Scientists often use natural substances to help them develop specific new medicines.

State two possible sources of such natural substances.

A

Microorganisms

Plants

34
Q

Explain why vaccinations are an example of active immunity.

A

antibodies produced by person being vaccinated

Memory cells remain in person being vaccinated

35
Q

Define the term parasite

A

lives on host

Gains nutrition from host but harms the host

36
Q

Explain why the human body’s primary defences do not prevent the entry of Plasmodium (e.h. malaria) into the body.

A

Vector feeds on blood

skin is not a barrier

37
Q

Suggest why malaria is much more common in tropical areas than in other parts of the world.

A

suitable climate for mosquitos, so many live there

38
Q

Outline the mode of action of antibodies in defending the body against pathogens by describing the processes of neutralisation

A

neutralisation
cover antigen on pathogen
Binds to toxins and prevents entry to host cell

39
Q

“Bacteria can evolve quickly and many are now immune to antibiotics.”

Explain why the student’s use of the word ‘immune’ was incorrect.

A

immunity involves an immune system
Immune is resistant
Bacteria is unicellular so cannot have an immune response

40
Q

Compare primary and secondary immune response

A

Primary immune response is slower because of clonal selection, expansion and production of antibodies

Secondary immune response is quicker because short lag time and more antibodies produces as memory cells are present.

41
Q

The graph shows the percentage of these samples that were methicillin-resistant (MRSA).
Suggest explanations for the positive correlation in the data in the graph.

A

Overprescription of methicillin
Not completing the course of methicillin
use of methicillin in farming

42
Q

Discuss the implications of the over-use of antibiotics when people do not show symptoms.

A

antibiotic is selective pressure
only some bacteria have resistance

when exposed to antibiotic most resistant survive
under continued antibiotic pressure, antibiotic becomes ineffective and new antibiotic needed.

43
Q

how is a structure of a neutrophil specialised

A

many lysosomes

lobed nucleus

44
Q

Viruses do not use erythrocytes as host cells, whereas the malarial pathogen Plasmodium spends part of its life cycle inside erythrocytes
Suggest why

A

Viruses are unable to replicate on its own

Plasmodium use erythrocytes as a source of food

45
Q

Explain why erythrocytes do not make use of any of the oxygen that they are transporting

A

Erythrocytes lack mitochondria, so no aerobic respiration

They are transported by mass flow so do not need energy

46
Q

What type of pathogen is the disease black Sigatoka

does it have a cell wall

A

Fungus

has a cell wall and membrane bound organelles

47
Q

Explain why the toxins produced by the different strains are described as immunologically distinct and how they will be dealt with by the immune system (6)

A
  • Antigen presenting cell ingest antigen and display antigen on their surfaces
  • Interaction between APC and T-helper cells produce interleukins
  • B cells activated by T helper cells go through clonal selection and expansion. Produces plasma and memory cells.
  • Antibodies are produced and bind to/neutralise toxins

It is immunologically distant because toxins produced by each strain is different.
Each toxin will have different amino acid sequence

48
Q

Explain what is meant by personalised medicine and synthetic biology

A

Personalised medicine - development of medicine linked to the individual’s genes
Synthetic biology - synthesis of new genes

49
Q

Explain the importance of maintaining biodiversity for the discovery of new antibiotics like phazolicin.

A

many drugs originated from plants

maintain biodiversity increases chance of developing new drugs and maintains a genetic resource.

A-Level OCR Biology (29 decks)

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