AQA Biology GCSE Topic 1: Cell Biology

Flashcards on cell biology, including cell structure, specialisation, division, and transport.

What type of cells are animal and plant cells?

Eukaryotic

Name three structures found in animal and plant cells.

Cell membrane, cytoplasm, and nucleus (containing DNA)

What type of cells are bacterial cells?

Prokaryotic

Name three structures found in bacterial cells.

Cell wall, cell membrane, and cytoplasm

What is the function of the nucleus in animal and plant cells?

Contains DNA coding for a particular protein needed to build new cells.

What is the function of the cytoplasm in animal and plant cells?

Liquid substance where chemical reactions occur and contains enzymes.

What is the function of the cell membrane in animal and plant cells?

Controls what enters and leaves the cell.

What is the function of mitochondria in animal and plant cells?

Where aerobic respiration reactions occur, providing energy for the cell.

What is the function of ribosomes in animal and plant cells?

Where protein synthesis occurs.

What is the function of chloroplasts in plant cells?

Where photosynthesis takes place, providing food for the plant.

What is the function of the permanent vacuole in plant cells?

Contains cell sap and improves the cell’s rigidity.

What is the function of the cell wall in plant cells?

Made from cellulose and provides strength to the cell.

What is cell specialisation?

A process that involves the cell gaining new sub-cellular structures in order for it to be suited to its role.

Describe the specializations of sperm cells.

Streamlined head and long tail to aid swimming, many mitochondria for energy, and acrosome with digestive enzymes.

Describe the specializations of nerve cells.

Long axon, many dendrites, and nerve endings with many mitochondria and neurotransmitters.

How do muscle cells cause movement?

Special proteins (myosin and actin) slide over each other, causing the muscle to contract.

Describe the specializations of root hair cells.

Large surface area due to root hairs, large permanent vacuole, and mitochondria for active transport.

Describe the specializations of xylem cells.

Lignin is deposited which causes the cells to die. They become hollow and are joined end-to-end to form a continuous tube so water and mineral ions can move through.

Describe the specializations of phloem cells.

Cell walls of each cell form structures called sieve plates when they break down, allowing the movement of substances from cell to cell.

What happens during cell differentiation?

Stem cells undergo differentiation by switching genes on or off to produce different proteins.

What is the function of adult stem cells?

Replace damaged cells.

Why are microscopes needed to view cells?

Extremely small structures such as cells cannot be seen without microscopes, which enlarge the image.

What is the formula of magnification of a light microscope?

Magnification of the eyepiece lens x magnification of the objective lens

What is the formula to calculate the size of an object under a microscope?

Size of image/magnification

What is a culture medium?

Contains carbohydrates for energy, minerals, proteins, and vitamins that microorganisms need to grow.

Why are Petri dishes and culture media sterilised before use?

To prevent contamination with other microorganisms.

What is the formula on how bacteria multiply?

Bacteria at beginning x 2 number of divisions = bacteria at end

What is the function of chromosomes?

Contain coils of DNA and carry many genes.

What happens during interphase in the cell cycle?

The cell grows, organelles grow, protein synthesis occurs, DNA is replicated, and energy stores increase.

What happens during mitosis in the cell cycle?

The chromosomes line up at the equator of the cell, and cell fibers pull each chromosome to either side of the cell.

What happens during cytokinesis in the cell cycle?

Two identical daughter cells form when the cytoplasm and cell membranes divide.

What are the two types of stem cells?

Embryonic stem cells and adult stem cells

Give an example of the benefit of research with stem cells.

Can be used to replace damaged or diseased body parts.

Give an example of the problems of research with stem cells.

We do not completely understand the process of differentiation, so it is hard to control stem cells to form the cells we desire.

What happens during diffusion?

Spreading out of the particles of any substance in solution, or particles of a gas, resulting in a net movement from an area of higher concentration to an area of lower concentration.

Name 4 things that affect the rate of diffusion.

Concentration gradient, temperature, surface area of the membrane and surface area to volume ratio

What is osmosis?

The movement of water from a less concentrated solution to a more concentrated one through a partially permeable membrane.

What is the function of active transport?

The movement of particles from an area where they are in lower concentration to an area where they are in higher concentration- against their concentration gradient.