B2 - Organisation Part 3

Question 1

What are communicable diseases?

Answer 1

Disease spread from person to person and are caused by pathogens

Question 2

What is cancer?

Answer 2

Uncontrolled growth and division of cells

Question 3

What is the difference between malignant and benign tumours? ( 2 marks)

Answer 3

Malignant: invades tissues and spread to different parts of the body to form secondary tumours that are cancerous
Benign: Contained in one area of the body - not cancerous

Question 4

What is health

Answer 4

Health is the state of physical and mental well-being.

Question 5

Name factors that can affect physical and mental health

Answer 5

diet, stress and life situations

Question 6

Explain how different types of diseases may interact
(4 marks)

Answer 6

Weak immune system means that an individual is more likely to suffer from infectious diseases.
* Viruses living in cells can be the trigger for cancers.
* Immune reactions initially caused by a pathogen can trigger allergies such as skin rashes and asthma.
* Severe physical ill health can lead to depression and other mental illness.

Question 7

Explain how lifestyle can have effect the rate of non-communicable diseases ( 4 marks)

Answer 7

In developed countries, non-communicable disease are more common as people generally have a higher income and can buy high fat food
People from deprived areas are more likely to smoke, have a poor diet and not exercise - cardiovascular disease, obesity Type 2 diabetes are higher in those areas

Question 8

Describe how some risk factors can cause a disease directly ( 6 marks)

Answer 8

Smoking - cardiovascular disease, lung disease and lung cancer - damages walls of arteries and the cells in the lining of the lungs
Obesity - Type 2 diabetes - body less sensitive/resistant to insulin - it struggles to control the concentration of glucose in the blood
Too much alcohol - liver disease, brain function - damaged nerve cells
Smoking when pregnant can cause lots of health problems for an unborn baby
Cancer can be directly caused by exposure to certain substances or radiation (Carcinogens)

Question 9

Explain why non-communicable disease can be costly ( 4 marks)

Answer 9

Cost to the NHS of researching and treating these diseases
Families may have to move or adapt their home to help a family member with a disease - costly
If a family member has to give up work/dies - family income will be reduced

Question 10

Explain the risk factors that can increase the chance of some cancers ( 4 marks)

Answer 10

Smoking - lung, mouth, bowel, stomach and cervical cancer
Obesity - Bowel, liver, kidney cancer
UV exposure - exposure to UV radiation from the Sun increase’s chance of developing skin cancer
Viral infection - infection with some viruses can increase the chance of developing certain types of cancer
For example, hepatitis B and C viruses can increase the risk of developing liver cancer

Question 11

What is the function of the Guard cell and stomata

Answer 11

Guard cell controls the size of the stomata to control water loss and gas exchange

Question 11

What is the function of the Waxy Cuticle

Answer 11

Reduces water loss from the leaf

Question 12

What is the function of the palisade mesophyll

Answer 12

Packed with chloroplasts to maximise photosynthesis

Question 13

What is the function of the spongy mesophyll

Answer 13

Contains air spaces to increase rate of gas diffusion

Question 14

What is the function of the xylem

Answer 14

Allows transport of water and mineral ions from the roots to the stem and the leaves

Question 15

What is the function of the phloem ( 3 marks)

Answer 15

Transports dissolved sugars from the leaves to rest of the plant for immediate use or storage
Transports in both directions
Translocation

Question 16

What is transpiration and translocation

Answer 16

Loss of water from plants
Movement of glucose around the plant

Question 17

Name four factors that increases the rate of transpiration ( 4 marks)

Answer 17

Light intesnity - brighter the light, the greater transpiration rate
Temperature - warmer it is, faster transpiration happens
Air flow - better air flow around a leaf - greater the transpiration rate
Humidity - drier the air around a leaf, the faster transpiration happens

Question 18

How is the stomata adapted for gas exchange and controlling water loss ( 6 marks)

Answer 18

Guard cells kidney shape - open and close stomata
When the plant has lots of water the guard cells fill with it and go plump and turgid - makes stomata open so gases can be exchanged for photosynthesis
When the plant is short of water, the guard cells lose water and become flaccid making the stomata close - helps stop too much water vapour escaping
Thin outer walls and thickened inner walls make the opening and closing work
Sensitive to light and close at night to save water without losing out on photosynthesis

Question 19

What is the function of the upper epidermis

Answer 19

Is transparent so that light can pass through it to the palisade layer

Question 20

How are tissues of leaves adapted for efficient gas exchange (4 marks)

Answer 20

Lower epidermis is full of little holes - stomata which lets CO2 diffuse directly into the leaf
Opening and closing of stomata is controlled by guard cells in response to environmental conditions
Air spaces in spongy mesophyll tissue increases rate of diffusion

Question 21

Function of epidermal tissue and meristem tissue

Answer 21

Covers the whole plant
Found out the growing tips of shots and roots and is able to differentiate into different types of plant cell allowing it to grow

Question 22

Describe the structure of the phloem tube
(2 marks)

Answer 22

Made of columns of elongated living cells with small pores in the end walls to allow cell sap through

Question 23

Describe the structure of xylem

Answer 23

Made of dead cells joined end to end with no end walls between them and a hole down the middle
Strengthened by lignin

Question 24

Explain how low light intensity affects rate of transpiration ( 3 marks)

Answer 24

Stomata begins to close as it gets darker.
Very little water can escape
Decreasing the rate of transpiration

Question 25

Explain how temperature affects the rate of transpiration ( 2 marks)

Answer 25

Higher the temperature
More energy water particles have to evaporate and diffuse out of stomata

Question 26

How does poor air flow affect the rate of transpiration (4 marks)

Answer 26

When air flow around a leaf is poor, water vapour just surrounds the leaf and doesn’t move away
Meaning there is a high conc of water particles outside the leaf as well as inside
Diffusion doesn’t happen as quickly

Question 27

How does humidity affect rate of transpiration ( 3 marks)

Answer 27

If air is humid there’s lots of water in it already
High conc of water particles outside the leaf as well as inside
Diffusion doesn’t happen as quickly