Aqa Gcse Biology Cells Flashcards
Tissue
A group of cells working together to perform a function E.g. Skin, muscle, liver, brain
Cell
The building blocks of all living organisms. Cells can be prokaryotic or eukaryotic
Eukaryote
Plant and Animal cells are eukaryotic cells as they have a cell membrane, cytoplasm and a nucleus
Prokaryote
Bacterial cells are prokaryotic cells as they are very very small have a cell wall around their cell membrane and they do not have a nucleus
Cell Membrane
An envelope that surrounds the cell and lets substances in and out
Nucleus
Contains DNA and controls the cells activity
Cytoplasm
The jelly centre of the cell which holds the sub-cellular structures and is where all the chemical reactions happen
Cell Wall
Only found in plant cells and bacterial cells. In plant cells the cell wall is made of cellulose
Single DNA Loop
In prokaryotic cells (bacteria) the DNA is found as a single loop
Plasmid
A small ring of DNA found in prokaryotic cells (bacteria)
Mitochondria
This is where respiration happens in cells which gives the cells energy
Chloroplasts
Only found in plant cells, these contain chlorophyll and are the sites of photosynthesis and are green
Ribosomes
Where proteins are made
Vacuole
Found in plant cells, these contain cell sap which is sugar and water
Specialisation
When a cell becomes specialised for a specific job. E.g. liver cells, heart cells, sperm cells.
Organ
An organ is made up of different tissues and has a specific job. E.g. the heart's job is to pump blood around the body.
Organ System
An organ system contains more than one organ working together. E.g. the cardiovascular system consists of the heart, lungs and blood.
Sperm Cells
A sex cell produced in the testes which carries genetic information from the male to the female egg. They have a tail to swim, lots of mitochondria for energy, and an acrosome which contains enzymes to digest through the egg membrane.
Nerve Cells
These are special cells which carry electrical impulses along a long structure called an axon. The brain is made of nerve cells. They are also known as neurones.
Muscle Cells
These make up muscle tissue and contract and relax to create movement. There are three types - smooth muscle, cardiac muscle and skeletal muscle. Muscle cells contain a lot of mitochondria as they need lots of energy
Root Hair Cell
A cell found in the roots of a plant which has a long part sticking out to increase the surface area for absorbing water and minerals. They also have NO chloroplasts as they do not photosynthesise
Xylem Cell
A cell that makes up xylem tissue in a plant. Xylem tissue is like a long tube that carries water from the roots of a plant to the leaves
Phloem Cell
A cell that makes up phloem tissue in a plant. Phloem tubes allow food like sugars to be moved around a plant.
Differentiation
The process that cells go through to become specialised.
Light Microscope
A microscope that uses light and a series of lenses to magnify things.
Electron Microscope
A microscope that fires electrons at objects and then creates a very detailed image.
What 3 organelles do plant cells have that animal cells don't? what do they do? (3)
- Chloroplast - absorb light for photosynthesis- vacuole - stores cell sap - structure and support (keeps cell rigid)- Cell wall - made of cellulose - structure and support
What are 4 key features of bacterial cells? (4)
- Small size- Cell wall- Cell membrane- loop of DNA (no nucleus)
describe how the body is organised starting at cells (3)
Cells - Tissue - Organs - Organ System
Meristems
Unspecialised cells (stem cells) in plants
Actual = Image / Magnification
Calculating actual size of a cell
1000
The number of micrometres in a mm