AQA GCSE Biology Paper 1 Review

Flashcards for AQA GCSE Biology Paper 1.

What is the formula for calculating magnification?

Magnification = Image Size / Object Size

What is the main structural difference between eukaryotic and prokaryotic cells?

Eukaryotic cells have a nucleus, while prokaryotic cells do not.

What is the function of the cell membrane?

Keeps everything inside the cell and is semi-permeable, allowing certain substances to pass through.

What is the function of mitochondria?

Where respiration takes place, releasing energy for the cell to function.

What is the purpose of aseptic technique in culturing bacteria?

To prevent contamination of the culture by unwanted microbes.

What is the difference between diploid and haploid cells in terms of chromosomes?

Diploid cells have pairs of chromosomes (23 pairs in humans), while haploid cells have half the number (23 in humans).

What is the main purpose of mitosis?

To create new cells for growth and repair.

What are stem cells?

Cells that have not yet specialized into a specific cell type.

Define diffusion.

The movement of molecules from an area of high concentration to an area of low concentration.

What is osmosis?

The diffusion of water across a semi-permeable membrane.

How can the rate of diffusion or osmosis be increased?

By increasing the concentration gradient, temperature, or surface area.

What is active transport?

The movement of substances across a membrane using energy, often against a concentration gradient.

What is the order of organization in living things?

Cells -> Tissues -> Organs -> Organ Systems

What is the role of bile in digestion?

Neutralizes stomach acid and emulsifies fats to increase surface area for enzyme action.

What are enzymes?

Biological catalysts that speed up chemical reactions.

Explain the lock and key principle of enzyme action.

The substrate must be the right shape to fit the enzyme's active site in order for a reaction to occur.

What happens when an enzyme denatures?

The active site changes shape, preventing the substrate from binding.

What is the optimum temperature or pH for an enzyme?

The temperature or pH at which the enzyme works most effectively.

How can you test for starch, sugars, proteins, and lipids?

Iodine for starch, Benedict's solution for sugars, Biuret reagent for proteins, and cold ethanol for lipids.

What is the difference between breathing and respiration?

Breathing provides oxygen for respiration, which is a chemical process within cells.

Describe the path of air through the respiratory system.

Trachea -> Bronchi -> Bronchioles -> Alveoli

What is the role of hemoglobin?

To bind to oxygen in red blood cells and transport it to the body's cells.

Why is the circulatory system called a double circulatory system?

Blood passes through the heart twice in each complete circuit of the body.

What is the function of arteries, veins, and capillaries?

Arteries carry blood away from the heart, veins carry blood towards the heart, and capillaries allow diffusion of molecules in and out of cells.

Outline the pathway of blood through the heart.

Vena Cava -> Right Atrium -> Right Ventricle -> Pulmonary Artery -> Lungs -> Pulmonary Vein -> Left Atrium -> Left Ventricle -> Aorta -> Body

What are stents and statins used for?

Stents keep blood vessels open, and statins reduce cholesterol to prevent fatty deposits.

Give an example of a communicable and a non-communicable disease.

Communicable: Measles. Non-communicable: Cardiovascular Disease.

What is the difference between benign and malignant cancers?

Benign cancers do not spread, while malignant cancers do.

What is the function of xylem and phloem?

Xylem transports water up the plant (unidirectional), and phloem transports sugars up and down the plant (bidirectional).

List three factors that increase the rate of transpiration.

Increasing temperature, decreasing humidity, and increasing air movement.

What are the main functions of the palisade mesophyll and spongy mesophyll layers in a leaf?

Palisade mesophyll is where most photosynthesis occurs, and spongy mesophyll provides space for gas exchange.

What is the function of stomata and guard cells?

Stomata are pores in the leaf for gas exchange, and guard cells control the size of the stomata.

Name four types of pathogens.

Viruses, bacteria, fungi, and protists.

How do viruses reproduce?

By injecting their genetic code into a cell, causing it to produce more copies of the virus until the cell explodes and releases new viruses.

Give an example of a disease caused by a protist, bacteria, fungi, and virus.

Protist: malaria, Bacteria: salmonella, Fungi: athlete's foot, Virus: measles.

How does the skin protect against pathogens?

It acts as a physical barrier to prevent entry.

What are the functions of lymphocytes and phagocytes?

Lymphocytes produce antibodies and antitoxins, and phagocytes ingest and destroy pathogens.

How do vaccines work?

By exposing the immune system to a dead or inert version of a pathogen, allowing it to produce antibodies without causing infection.

Do antibiotics kill viruses or bacteria?

Bacteria.

What is the purpose of a double-blind trial?

To eliminate bias by ensuring that neither the test subjects nor the analysts know which group is receiving the drug.

Write the balanced chemical equation for photosynthesis.

6CO2 + 6H2O -> C6H12O6 + 6O2

Name three factors that can increase the rate of photosynthesis.

Increasing temperature, light intensity, or CO2 concentration.

Write the balanced chemical equation for aerobic respiration.

C6H12O6 + 6O2 -> 6CO2 + 6H2O

What is the product of anaerobic respiration in animal cells?

Lactic acid.

What is the product of anaerobic respiration in plant and yeast cells?

Ethanol and carbon dioxide.

Define metabolism.

The sum of all reactions in a cell or organism.