Tricky Topics (paper 1) 🫁🪴

Question 1

What are the alveoli?

Hint: tiny

Answer 1

tiny air sacs where gas exchange takes place

Question 2

What is the trachea?

Hint: airway + cartilage

Answer 2

An airway which is often kept open by rings of cartilage

Question 3

What are the bronchioles?

Hint: branches + bronchi

Answer 3

tiny branches of the bronchi that carry air to the alveoli

Question 4

What is the diaphragm?

Answer 4

a sheet of muscles at the base of the ribcage

Question 5

What is the bronchi?

Hint: tubes

Answer 5

tubes that connect the trachea to the lungs

Question 6

What are the intercostal muscles?

Answer 6

muscles that raise and lower the ribcage

Question 7

What are the steps for mitosis and cytokinesis?

Answer 7

1) DNA condenses to form chromosomes.

2) chromosomes line up along the centre of the cells.

3) cell fibres pull the two arms of each chromosome to opposite piles of the cell.

4) cytokinesis- the entire cell divides to form two identical daughter cells.

Question 8

What is the equation for breathing rate?

Answer 8

Breathing rate= no. of breaths
___________________
time

Question 9

Why is an enzyme? [2]

Answer 9

A catalyst that speeds up the rate of reaction, and has an active site.

Question 10

Humans and plants use glucose. Give one reason why humans and plants use glucose. [2]

Hint: convert + carbohydrates

Answer 10

Plants:
- to convert into insoluble starch for storage.

Humans:

• to convert to new carbohydrates.

Question 11

A plant has TMV. All tools should be disinfected after using them on plants with this virus. Suggest why [1]

Answer 11

• to kill the virus

Question 12

A group of scientists managed to produce a single plant that had a TMV- resistant gene.

Suggest how scientists can use this plant to produce many plants with the same resistant gene.

Answer 12

• use stem cells of plants, from meristem

Question 13

In the practical that tests for the rate of photosynthesis using: a glass test tube, pondweed, a thermometer, water at 20c and a beaker. Explain why it was important to use a thermometer?

Hint: What are you measuring?

Answer 13

• to measure temperature

Question 14

Multicellular organisms often have complex structures (e.g lungs- for gas exchange). Explain why single- cell organisms such as algae don’t need a complex structure for gas exchange.

Answer 14

• cell has a larger surface area : volume ratio, so diffusion has a short distance.

Question 15

An algae cell has a flagellum which helps the cell to move through water. Scientists think that the flagellum and the light-sensitive spot work together to increase photosynthesis.

Suggest how this could happen.

Answer 15

• light sensitive spur detects light + tells flagellum to move towards light.
• more light= more photosynthesis.