AQA Biology GCSE Topic 1: Cell Biology

Flashcards on Cell Biology

What are the two types of cells?

All living things are made of cells, which can either be prokaryotic or eukaryotic.

What are the three main components of animal and plant cells?

Cell membrane, cytoplasm, and a nucleus containing DNA

What components do bacterial cells have?

Cell wall, cell membrane, cytoplasm, single circular strand of DNA, and plasmids.

What are organelles?

Structures in a cell that have different functions.

What is the function of the nucleus?

Contains DNA coding for a particular protein needed to build new cells and is enclosed in a nuclear membrane.

What is the function of the cytoplasm?

Liquid substance in which chemical reactions occur, contains enzymes, and houses organelles.

What is the function of the cell membrane?

Controls what enters and leaves the cell.

What is the function of the mitochondria?

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

What is the function of the ribosomes?

Where protein synthesis occurs.

What is the function of the chloroplasts?

Where photosynthesis takes place, providing food for the plant, and contains chlorophyll.

What is the function of the permanent vacuole?

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.

What are the specializations of a sperm cell?

Streamlined head and long tail; many mitochondria; an acrosome with digestive enzymes.

What are the specializations of a nerve cell?

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

What are the specializations of a muscle cell?

Special proteins (myosin and actin); lots of mitochondria; ability to store glycogen.

What are the specializations of a root hair cell?

Large surface area due to root hairs; large permanent vacuole; mitochondria.

What are the specializations of a xylem cell?

Lignin deposition, causing cells to die and become hollow, forming a continuous tube.

What are the specializations of a phloem cell?

Cell walls form sieve plates; energy supplied by mitochondria of companion cells.

What is cell differentiation?

To become specialised and be suited to its role, stem cells must undergo differentiation to form specialised cells.

What is the purpose of microscopes?

Enlarge images of extremely small structures such as cells.

What are the two lenses in a light microscope?

Objective and eyepiece.

How does an electron microscope work?

Electrons are used to form an image because they have a much smaller wavelength than light waves.

What are the two ways to grow microorganisms in the lab?

In nutrient broth solution and on an agar gel plate.

How to calculate the number of bacteria in a population after a certain time?

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

How are genes and chromosomes related?

Each chromosome carries many genes.

What is the cell cycle?

Series of steps that the cell has to undergo in order to divide, mitosis is the stage when the cell divides.

What are the three stages of the cell cycle?

Interphase, Mitosis, Cytokinesis

What is a stem cell?

An undifferentiated cell which can undergo division to produce many more similar cells, of which some will differentiate to have different functions.

What are the types of stem cells?

Embryonic stem cells, adult stem cells, and plant meristems.

Define osmosis.

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

What happens to animal cells in a dilute solution?

Water will move in, causing them to burst.

What happens to plant cells in a dilute solution?

Water will move into the cell and into the vacuole, causing it to swell, resulting in pressure called turgor.

Define active transport.

Movement of particles from an area where they are in lower concentration to an area where they are in higher concentration.