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 beliefs

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

What happens during the division stage of mitosis? [3]

Chromosomes line up at the centre of the cell and chromosomes are pulled by fibres to each end of the cell, dividing the nucleus

What are the units of distance from smallest to largest? (5, ending with kilometre)

NUMMK - nanometre (nm), micrometre (µm), millimetre (mm), metre (m), kilometre (km)

How can you use oxygen produced by a plant to measure the rate of photosynthesis?

Measuring the volume produced in a given time

Why does a white leaf mean its dying? [2]

Lacks green chlorophyll so doesn’t absorb light for photosynthesis to occur

Why is it difficult to develop drugs to destroy viruses?

It’s hard to get the drugs into living cells

Suggest why doctors are concerned about antibiotic resistance [2]

Current antibiotics don’t kill certain bacteria so new ones need to be developed, taking time and money

Name the process that transports dissolved sugars around a plant

Translocation

Describe the process of transpiration

A plant opens its stomata to let in carbon dioxide, allowing water from the spongy and palisade mesophyll evaporate and diffuse out of the leaf

Describe how to test for sugar in a food substance

Boil it with Benedict’s reagent, turning it from blue to red.

Explain how a lack of oxygen in the blood will affect the human body?

Less aerobic respiration so less energy released so less muscle contraction

What type of drug lowers blood cholestrol?

statins

Explain how a stent works

Widens blocked blood vessel, allowing more blood to flow

Explain why applying pressure to the heart helps someone who’s not breathing helps them

Pushes blood to get oxygen around the body

Which blood vessels are affected by coronary heart disease?

Arteries

Where in the heart are the pacemaker cells? How do they make the heart beat?

In the right atrium wall, they produce an electrical impulse spreading to the surrounding muscle cells, making them contract

What are the two main problems with surgery?

Can lead to bleeding and infection

Compare (Describe the similarities and differences between) the processes of catalytic and steam cracking [5]

• Both first vaporise long chain hydrocarbons

• However catalytic passes the vapour over hot powdered aluminium oxide catalyst, molecules splitting apart on its surface

• Whereas steam cracking mixes the vapour with steam, heating to a high temperature to split apart

Describe the first stage of clinical trials [3]

The drug is tested on healthy and infected volunteers at very low doses to test for side effects, then, if safe, dosage is increased to find optimum dosage

How are monoclonal antibodies produced? [6] (a,s,t,c,dp,cp)

1. Mouse injected with specific antigen

2. Mouse lymphocytes stimulated to produce specific antibody

3. Lymphocytes combined with fast-dividing tumour cell, producing a hybridoma

4. Hybridoma is cloned

5. Hybridoma divides rapidly and produces antibody

6. Large amount of antibody collected and purified

What are the three physical, three mechanical and two chemical plant defences?

Physical - dead cell layers around stems, waxy cuticle, cellulose cell walls

Mechanical - thorns and hairs, drooping/curling leaves, mimicing organisms

Chemical - producing antibacterial chemicals or poison

How do bacteria and viruses make us feel ill?

Bacteria - may produce toxins that damage tissues, making us feel ill

Viruses - live and reproduce inside cells, causing cell damage

How can fungi cause disease?

Hyphae grow and penetrate human skin or the surface of plants

What are the signs of tobacco mosaic virus

A mosaic pattern of discolouration, reducing photosynthesis, impairing growth

What type of disease is rose black spot, what effect does it have, how is it spread and how is it treated

• A fungal disease

• Causes purple spots to develop on leaves, making them turn yellow and drop early. Impairs growth as photosynthesis is reduced.

• Spread in the environment by water or wind

• Treated with fungicides or removing and destroying infected leaves.

What are the symptoms of gonorrhoea and how is its spread controlled?

• Symptoms include pain when urinating and thick yellow/green discharge from v*gina or p*enis.

• Treating with antibiotics or using barrier contraception (e.g. c*ndom)

What are antibiotics used for? Give an example of an antibiotic

Used to kill, or prevent growth of bacteria e.g. penicillin

Why may fluorsecent dye be added to monoclonal antibodies?

To locate or identify specific molecules in a cell or tissue