Biology GCSE paper 1 missed questions

Why does vaccinating children reduce the spread of a pathogen in a population? [2]

Fewer people with pathogen so less likely for pathogen to spread

Where is Pepsin produced?

The stomach

Which four factors affect rate of photosynthesis?

1. Light intensity

2. Light colour

3. Carbon dioxide concentration

4. Chlorophyll mass

How should rate of photosynthesis be measured in the photosynthesis practical?

Collect oxygen in a gas syringe

What three methods can be used to identify a plant disease?

1. Reference a gardening manual/website

2. Take infected plants to a laboratory

3. Use testing kits containing monoclonal antibodies

What are four things transported by blood plasma?

1. Hormones

2. Antibodies

3. Proteins

4. Ions

5. Enzymes

6. Urea

7. Glucose

8. Carbon dioxide

Describe the structure of artery walls

Thick elastic/muscular layer

Why is anaerobic respiration less efficient than aerobic? [2]

Releases less energy per molecule of glucose due to incomplete breakdown of glucose

Why is oxygen continually used after exercise?

Oxygen debt means more oxygen is required to oxidise lactic acid

Why is having more blood cells an advantage for an athlete?

More haemoglobin so more oxygen is carried around the body, allowing more aerobic respiration to release more energy

Define diffusion

The net movement of particles from a higher to lower concentration, down a concentration gradient

What are the four ways gills are adapted for oxygen exchange?

1. Filaments provide large surface area to maximise diffusion

2. Good blood supply to maintain concentration gradient

3. Thin filament walls for short diffusion distance

4. Blood supply close to water for short diffusion distance

Why does a fish’s metabolic rate increase when swimming vs resting? [4]

Increased movement, needing more energy, requiring more respiration for muscle contraction

What property of embryonic stem cells make them suitable to treat liver disease?

They can differentiate into any type of cell

What is an ethical reason why someone may not want an embryonic stem cell injection?

• Destroying embryo

• Embryo cannot give consent

• Against personal veliefs

How do monoclonal antibodies prevent white blood cells attacking a donor organ? [3]

Monoclonal antibodies bind to organ antigens as they are complementary to the antigens, preventing antibodies released by white blood cells from binding to donor organ antigens

What are the two main purposes of bile in digestion?

• Emulsifies fats to increase their surface area for enzymes

• Neutralising pH of stomach acid in small intestine for optimum enzyme pH

When cells on a culture medium are too close to count, how can you count them?

Dilute each sample to count the total cells

What does ‘pulmonary’ refer to

Related to the lungs

Where are pacemaker cells located?

The right atrium

Why is the human circulatory system a ‘double circulatory system’?

Blood passes through the heart twice per circuit

What are chromosomes?

a long, coiled DNA molecules carry in genetic information as genes

How do plant stem cells differ from human ones?

They can differentiate into any plant cell throughout the entire life of the plant

how are embryonic stem cells used to treat diabetes and people paralysed by a spinal injury?

Diabetes- making insulin-producing cells nerve cells

Paralysed- making new nerve cells

What is the main risk of stem cells in medicine?

Stem cells grown in a lab can be contaminated with a virus, passing it onto the patient