AQA Biology GCSE: Cell Biology

Made with AI using Physics and Maths tutors' Detailed notes on cell biology.

Eukaryotes

Living things made of cells that can be prokaryotic or eukaryotic.

Prokaryotes

Cells that are much smaller than eukaryotic cells

Organelles

Structures in a cell that have specific functions

Orders of Magnitude

A way to understand the size difference between objects

Prefixes

Added before units of measurement to indicate multiples

Nucleus

Cell organelle containing DNA and enclosed in a nuclear membrane.

Cytoplasm

Liquid substance in cells where chemical reactions occur

Cell Membrane

Controls the movement of substances into and out of the cell.

Mitochondria

Organelles where aerobic respiration reactions occur

Ribosomes

Organelles where protein synthesis occurs

Chloroplasts

Organelles in plant cells where photosynthesis takes place

Permanent Vacuole

Organelle in plant cells containing cell sap

Cell Wall

Structure made of cellulose providing strength to plant and algal cells.

Plasmids

Small rings of DNA found in bacterial cells

Cell Specialisation

Process where cells gain specific structures to perform particular functions

Stem Cells

Cells that can differentiate into various cell types

Differentiation

Process where stem cells develop into specialized cells by switching genes on or off to produce specific proteins.

Mitosis

Process of cell division producing 2 identical cells

Red Blood Cells

Cells without nuclei

Adult Stem Cells

Cells retaining ability to differentiate

Repair in Animals

Cell division for damaged cell replacement

Cell Differentiation in Plants

Cells differentiate at final position

Microscopy

Method to view small structures like cells

Light Microscope

Instrument using light for magnification

Electron Microscope

Instrument using electrons for deep structure viewing

Magnification Formula

Eyepiece lens magnification x objective lens magnification

Standard Form

Representation of large/small numbers using powers of 10

Culture Medium

Nutrient-rich environment for microorganism growth

Nutrient Broth Solution

Suspension of bacteria in nutrient broth for growth

Agar Gel Plate

Surface for bacteria growth

Autoclave

Device for sterilizing Petri dishes and media

Inoculating Loops

Wire loops used to spread microorganisms on agar

Incubation

Process of storing for microorganism growth

Binary Fission

Bacteria reproduction by splitting into two

Antibiotics Testing

Testing effects of antibiotics on bacterial growth

Inhibition Zone

Clear area showing antibiotic effectiveness

Antibiotic Resistance

Bacteria that are resistant to antibiotics survive

Zone of Inhibition

Area around an antibiotic disk where bacteria do not grow

Cross-Sectional Area Calculation

Calculated using the formula πr²

Chromosomes

Coils of DNA containing genes that code for proteins and carry genetic information.

Gene

Short section of DNA that codes for a protein and controls a characteristic.

Pairs of Chromosomes

There are 23 pairs of chromosomes in each cell

Interphase

Stage where the cell grows

Cytokinesis

Stage where cytoplasm divides

Stem Cell

Undifferentiated cell capable of dividing and differentiating into various cell types.

Embryonic Stem Cells

Derived from embryos

Meristems

Plant stem cells found in root and shoot tips

Therapeutic Cloning

Production of an embryo with the same genes as the patient for harvesting stem cells.

Diffusion

Process of particles spreading from an area of higher concentration to lower concentration.

Gas Exchange

Movement of gases like oxygen and carbon dioxide between the lungs and red blood cells.

Factors Affecting Diffusion

Include concentration gradient

Surface area to volume ratio

The size of the surface area of the organism compared to its volume. Calculated by finding the volume (length x width x height) and the surface area (length x width)

Single-celled organisms

Organisms that consist of only one cell

Multicellular organisms

Organisms composed of multiple cells

Alveoli

Millions of air sacs in the lungs where oxygen is transferred to the blood and carbon dioxide is transferred to the lungs.

Villi

Projections in the small intestine that increase the surface area for absorption of digested food into the bloodstream.

Gills

Respiratory organs in fish where gas exchange occurs

Root hair cells

Cells in plant roots with large surface areas that project into the soil for water and mineral ion uptake.

Stomata

Small openings on the surface of leaves that allow for gas exchange

Osmosis

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

Hypertonic solution

A solution with a higher concentration of solutes compared to the cell

Hypotonic solution

A solution with a lower concentration of solutes compared to the cell

Isotonic solution

A solution with the same concentration of solutes as the cell

Turgor

Pressure within plant cells caused by water uptake

Plasmolysis

The process in plant cells where the cell membrane moves away from the cell wall due to water loss

Active transport

The movement of particles from an area of lower concentration to an area of higher concentration