S2 Biology - Body systems and cells 2

Question 1

What are the three classifications of microorganisms?

Answer 1

Fungi, bacteria and viruses

Question 2

What do we need to view microorganisms?

Answer 2

A microscope

Question 3

Which group of microorganisms are the smallest?

Answer 3

Viruses

Question 4

Which type of microorganisms are the largest?

Answer 4

Fungi

Question 5

Are bacteria smaller or bigger than fungi?

Answer 5

smaller

Question 6

Name 4 factors which are essential for microbial growth.

Answer 6

Food source, e.g. glucose (sugar)
Water
Warm temperature
Suitable pH

Question 7

What is cell division?

Answer 7

Cell dividion is the process by which bacteria and yeast cell reproduce; the parent cell divides into two new identical cells.

Question 8

Starting with 2 cells which divide every 20 minutes, how many cells would you have after 3 hours?

Answer 8

1024 cells
Working:
2-> 4-> 8-> 16-> 32-> 64-> 128 -> 256 -> 512 -> 1024

Question 9

A type of bacterial cell divides every 45 minutes. How many cells do you have after 6 hours?

Answer 9

256
Working:
1 -> 2 -> 4 -> 8 -> 16 -> 32 -> 64 -> 128 -> 256

Question 10

Starting with 17 cells, how many cells do you have after one division?

Answer 10

34 (one division doubles the number of cells)

Question 11

What is the independent variable?

Answer 11

The factor you are changing in an investigation.

Question 12

When investigating the effect of pH on the growth of microbes, what variables need to be kept constant (controlled variables)?

Answer 12

Temperature or number of cells at the start or concentration of microbes at the start or type & concentration of food supplied to mircobes

Question 13

How could you ensure the temperature in an investigation stays the same?

Answer 13

Use a waterbath or incubator

Question 14

Give an example of a situation where the growth of microbes is restricted to preserve food.

Answer 14

Keeping meat and dairy products at 4 degrees C (in the fridge); drying food (no water for microbes to grow); pickles (low pH prevents growth of microbes)

Question 15

What microorganisms is used to make bread?

Answer 15

Yeast

Question 16

What products can be made with the help of yeast?

Answer 16

Bread, beer, wine

Question 17

What makes dough rise?

Answer 17

The yeast inside the dough is producing carbon dioxide (gas) which makes the dough rise.

Question 18

What two things does yeast produce when it feeds on sugars which help in the production of drinks?

Answer 18

Alcohol & carbon dioxide

Question 19

What substances can be used to control the growth of bacteria?

Answer 19

Antibiotics

Question 20

What does it mean if bacteria are ‘resistant’ to antibiotics?

Answer 20

The antibiotics do not stop the growth of the bacteria (i.e. they do not work against these bacteria).

Question 21

In which parts of your body can fungi find ideal growing conditions?

Answer 21

Between toes
Under arm pits
Mouth
Reproductive tract

Question 22

What do you call medicines that treat infections caused by fungi?

Answer 22

Antifungals

Question 23

What effect does increasing the temperature have on the growth of microbes?

Answer 23

The more the temperature increases the more the microbes grow, until it gets too hot for them and then they stop growing and die.

Question 24

What is a pathogen?

Answer 24

A pathogen is a disease-causing microorganism

Question 25

Give 3 examples of pathogens.

Answer 25

Some bacteria, e.g. those causing pneumonia, food poisening or whooping cough;
Some fungi, e.g. those causing athlete’s foot or ringworm
All viruses, e.g. chickenpox, measles, flu

Question 26

Why does the body have a ‘first line of defence’?

Answer 26

To prevent microbes form entering the body or entering the blood stream.

Question 27

Give examples of the first line of defence of your body (7)

Answer 27

Nose hairs
Eyelashes
Tears
Stomach acid
Saliva
Cillia & mucus
Skin

Question 28

Name two types of white blood cells.

Answer 28

Phagocytes & lymphocytes

Question 29

What is the function of the phagocytes?

Answer 29

Phagocytes surround and engulf pathogens that manage to get into the body, and then destroy them using special chemicals (enzymes).

Question 30

Which cells engulf pathogens to destroy them?

Answer 30

Phagocytes (a type of non-specific white blood cell)

Question 31

Why are lymphocytes described as ‘specific’ white blood cells?

Answer 31

Each type of lymphocyte only produces antibodies against a specific type of pathogen; e.g. antibodies produced against the chickenpox virus will only bind to this specific virus but no other virus.

Question 32

Describe the role of lymphocytes in the immune response.

Answer 32

Lymphocytes target specific pathogens by making antibodies which bind to the antigens (surface structures) on the surface of pathogens; antibodies are specific against one type of pathogen/ antigen.

Question 33

What is meant by immunological memory?

Answer 33

After an initial infection, when the person come sin contact with the same pathogen again, the lymphocytes make the required antibodies much faster and at higher concentrations as they are already familiar with the pathogen.

Question 34

The train the body’s immune system, vaccines may contain…

Answer 34

…
weaker forms of pathogens
dead pathogens
parts of pathogens
antigens of pathogens
genetic information for the body to make the pathogen’s antigen (e.g. Covid spike protein)

Question 35

Is it more or less likely for a pathogen to spread if more people are vaccinated?

Answer 35

It is less likely for a pathogen to spread if more people are vaccinated.