Paper 1

Question 1

Function and adaptation of the Waxy Cuticle

Answer 1

Reduces evaporation and lets light through.

They’re waterproof and transparent.

Question 2

Function and adaptation of the Upper Epidermis.

Answer 2

Layers of cells allowing light through it.

Transparent, single layer cells.

Question 3

Function and adaptation of the Palisade mesophyll

Answer 3

Photosynthesis.

Many chloroplasts and columnar cells are numerous.

Question 4

Function and adaptation of the Xylem Tissue

Answer 4

Transports water and mineral ions from roots to leaves (transpiration)
Tissues are made of hollow vessels.
Lose their end walls so the xylem forms a continuous, hollow tube.
Become strengthened by a chemical called lignin. The cells are no longer alive. Lignin gives strength and support to the plant.

Question 5

Function and adaptation of the Phloem Tissue

Answer 5

Transports sucrose to other parts (translocation)
Companion cells control the direction of sucrose transport in sieve cells.
- transport of substances in the phloem requires energy. One or more companion cells attached to each sieve tube provide this energy

Question 6

Function and adaptation of the Spongy mesophyll

Answer 6

Gases dissolve and evaporate on cell surfaces/some photosynthesis.
Cell surface is moist/some chloroplasts.

Question 7

Function and adaptation of the Lower Epidermis

Answer 7

Gaseous exchange where they leave and enter on this surface.

Many stomata and guard cells.

Question 8

Function and adaptation of the stomata

Answer 8

Holes which permit gaseous exchange.

Contains two guard cells which can change shape.

Question 9

How have leaves adapted for gaseous exchange?

Answer 9

Thin - decreases distance
Big surface area - more room for stomata
stomata holes - somatal holes permit gases in/out

Question 10

What substances pass through stomatal pores?

Answer 10

Water vapour
Oxygen
Carbon Dioxide

Question 11

Why is there a higher concentration of stomata on the underside of the leaf?

Answer 11

The shaded surface is cooler so more stomata need to be used for gaseous exchange.
The sun will evaporate water on the upper side.

Question 12

What do guard cells do?

Answer 12

They open and close the stomata (the space between guard cells)

Question 13

Describe how stomata open and close at day and night.

Answer 13

Water passes into the cells during the day by osmosis which makes them bend and hence open.
Water passes out of the cells during the night by osmosis which makes them straighten up and close.

Question 14

Describe how you could show that plants growing in warmer climates have less stomata on their leaves than plants growing in temperature climates.

Answer 14

• Obtain a leaf from both species of plant.
• Paint a thin film of nail vanish on the leaves.
• Allow the vanish to dry and peel it off.
• Mount the lower surface peel of one of the leaves onto a mic slide.
• Count the number of stomatal imprints in the field of view.
• Obtain two or more sets of results with this leaf and surface.
• Repeat the above with the lower surface of the other species of leaf.

Question 15

Where are the xylem found and what do they transport?

Answer 15

In stem roots and leaves.

They transport water and mineral ions up the root system to the leaves.

Question 16

Define Transpiration

Answer 16

The movement of H20 up the root system to the leaves because of the loss of water in the leaves due to evaporation.

Question 17

What is the xylem wall made of?

Answer 17

Cellulose and lignin

Question 18

What is the function and adaptation of the lignin?

Answer 18

It supports the plant and keeps the water in.

It’s made of strong and waterproof material.

Question 19

How is energy is provided for the translocation of sucrose in the sieve cells?

Answer 19

Companion cells have mitochondria which do aerobic respiration.

Question 20

Describe the route of transpiration of water.

Answer 20

• The concentration of water is higher in the soil than in the plant’s root cells.
• The water moves into the plant root cells by osmosis.
• Xylem vessels take the water from the root and stem to the leaves.
• The water is pulled up as evaporation looses water in the leaves.
• Inside the leaf the water evaporates becoming water vapour which moves through the spaces of the spongy mesophyll.
• The water vapour leaves the leaf through the stomata pores (underside of the leaf)

Question 21

Name three factors which affect the rate of transpiration.

Answer 21

Humidity (wetness in the air) - decreases the rate
Wind speed - Increases the rate
Temperature - Increases the rate

Question 22

Potometer

Answer 22

A device that measures the water uptake in a plant.

Question 23

Difference between translocation and transpiration

Answer 23

Translocation

• requires energy
• products of phs
• goes upwards and downwards

Transpiration

• physical process (no energy)
• water and minerals
• upwards

Question 24

What are pathogens

Answer 24

Microorganisms that cause

infectious disease eg viruses, bateria, protists and fungi

Question 25

How do pathogens spread?

Answer 25

They can infect plants or animals, spreading through either direct contact, by water or by air.

Question 26

How do viruses make an individual ill?

Answer 26

They move into cells and use the biochemistry of it to make many copies of itself ● This leads to the cell bursting and releasing all of the copies into the bloodstream ● The damage and the destruction of the cells makes the individual feel ill

Question 27

How do bacteria make an individual ill?

Answer 27

They multiply very quickly through dividing by a process called binary fission ● They produce toxins that can damage cells

Question 28

How do protists make an individual ill?

Answer 28

They use humans and animals as their hosts (live on | and inside, causing damage)

Question 29

Different types of fungi

Answer 29

They can either be single celled or have a body made of hyphae (thread-like structures)

Question 30

How do fungi spread?

Answer 30

They can produce spores which can be spread to other organisms

Question 31

How are diseases spread?

Answer 31

Direct contact- touching contaminated surfaces eg kissing, contact with bodily fluids, direct skin to skin, microorganisms from faeces, infected plant material left in field By water- drinking or coming into contact with dirty water By air- pathogens can be carried in the air and then breathed in (a common example is the droplet infection, which is when sneezing, coughing or talking expels pathogens in droplets which can be breathed in)

Question 32

How can you limit the spread of pathogens?

Answer 32

Improving hygiene: Hand washing, using disinfectants, isolating raw meat Reducing contact with infected individuals Removing vectors: Using pesticides or insecticides and removing their habitat Vaccination: By injecting a small amount of a harmless pathogen into an individual’s body, they can become immune to it so it will not infect them. This means they cannot pass it on.

Question 33

Symptoms, spread and prevention of measles (v)

Answer 33

Symptoms: Fever and red skin rash, can lead to other problems such as pneumonia (lung infection), encephalitis (brain infection) and blindness. How it is spread: Droplet infection How it is being prevented: Vaccinations for young children to reduce transmission

Question 34

Symptoms, spread and prevention of HIV (v)

Answer 34

Symptoms: Initially flu-like symptoms, then the virus attacks the immune system and leads to AIDS (a state in which the body is susceptible to many different diseases) How it is spread: By sexual contact or exchange of bodily fluids such as blood How it is being prevented: ● The spread- Using condoms, not sharing needles, screening blood when it is used in transfusions, mothers with HIV bottle-feeding their children instead of breastfeeding ● The development to AIDS- Use of antiretroviral drugs (stop the virus replicating in the body)

Question 35

Symptoms, spread and prevention of TMV (v)

Answer 35

Symptoms: Discolouration of the leaves, the affected part of the leaf cannot photosynthesise resulting in the reduction of the yield. How it is spread: Contact between diseased plants and healthy plants, insects act as vectors. How it is being prevented: Good field hygiene and pest control, growing TMV-resistant strains.

Question 36

Symptoms, spread and prevention of salmonella (b)

Answer 36

Symptoms: Fever, stomach cramps, vomiting, diarrhoea (all caused by the toxins they secrete). How it is spread: These bacteria can be found in raw meat and eggs, unhygienic conditions. How it is being prevented: Poultry are vaccinated against Salmonella, keeping raw meat away from cooked food, avoid washing it, wash hands and surfaces when handling it, cook food thoroughly.

Question 37

Symptoms, spread and prevention of gonorrhea (b)

Answer 37

Symptoms: Thick yellow or green discharge from the vagina or penis, pain when urinating. How it is spread: It is a sexually transmitted disease spread through unprotected sexual contact. How it is being prevented: By using contraception such as condoms and antibiotics (used to be treated with penicillin but many resistant strains are developing).

Question 38

Symptoms, spread and prevention of rose black spot (f)

Answer 38

Symptoms: Purple or black spots on leaves of rose plants, reduces the area of the leaf available for photosynthesis, leaves turn yellow and drop early How it is spread: The spores of the fungus are spread in water (rain) of by wind How it is being prevented: By using fungicides or stripping the plant of affected leaves (have to be burnt)

Question 39

Symptoms, spread and prevention of malaria (p)

Answer 39

(caused by protist pathogens that enter red blood cells and damage them) Symptoms: Fevers and shaking (when the protists burst out of blood cells) How it is spread: The vector is the female Anopheles mosquito, in which the protists reproduce sexually. When the mosquito punctures the skin to feed on blood, the protists enter the human bloodstream via their saliva. How it is being prevented: Using insecticide coated insect nets while sleeping, removing stagnant water to prevent the vectors from breeding, travellers taking antimalarial drugs to kill parasites that enter the blood.

Question 40

Human Defence System

Answer 40

Skin Nose Trachea and bronchi Stomach

Question 41

How does the skin prevent pathogens from entering the body?

Answer 41

Acts as a physical barrier ● It produces antimicrobial secretions to kill pathogens ● Good microorganisms known as skin flora compete with the bad microorganisms for space and nutrients

Question 42

How does the nose prevent pathogens from entering the body?

Answer 42

Has hairs and mucus (sticky substance) which prevent particles from entering your lungs

Question 43

How does the trachea and bronchi prevent pathogens from entering the body?

Answer 43

Secrete mucus in order to trap pathogens ● Cilia (hair-like structures on cells) beat to waft mucus upwards so it can be swallowed

Question 44

How does the stomach prevent pathogens from entering the body?

Answer 44

Produces hydrochloric acid that kills any pathogens in your mucus, or food and drink

Question 45

infection and response

Answer 45

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