Cell Biology Flashcards
What is a eukaryotic cell
A cell with a nucleus
What is a prokaryotic cell
A cell without a nucleus
What things do all eukaryotic cells have
Nucleus - controls activities of the cell
Cytoplasm - Where most of the chemical reactions happen
Cell membrane - Holds the cell together and controls what goes in and out
Mitochondria - Most reactions for aerobic respiration occur here
Ribosomes - where proteins are synthesised
What extra bits do plant cells have
Cell wall - supports and strengthens the cell
Permanent vacuole - contains cell sap
Chloroplasts - Where photosynthesis occurs
What do bacterial cells have
Cell membrane
Cytoplasm
Cell wall
Plasmids
How big are bacterial cells
0.2-2.0 micrometres
What do light microscopes do
Use light and lenses to form an image of a specimen and magnify it
What do electron microscopes do
Use electrons instead of light to form an image
They have a much higher resolution and magnification
What is the equation for magnification
Magnification = image size/ real size
What is cell differentiation
Where a cell changes to become more specialised for their specific functions
How are sperm cells adapted for reproduction
Long tail and streamlined head for swimming
Lots of mitochondria for energy
Enzymes in head to digest through egg membrane
How are nerve cells specialised for rapid signalling
Long axon to cover more distance
Branched connections to connect to other nerve cells and create a network
How are muscle cells specialised for contraction
Long so they have space to contract
Lots of mitochondria for energy
How are root hair cells specialised for the uptake of minerals and ions
Have long hairs which increase SA for uptake
Mitochondria for active transport
How is xylem specialised for the uptake of water and minerals
Hollow so water and minerals can flow through
Lignin is deposited in spirals to withstand the pressure
Why is mitosis important
To grow or replace cells that have been damaged
Stages of mitosis
Prophase
Metaphase
Anaphase
Telophase
Cytokinesis
Describe mitosis
DNA duplicates
Chromosomes line up at the centre of the cell and the cell fibres pull them apart
Membranes form around the 2 sets of chromosomes
Cytoplasm and cell membrane divide
2 identical daughter cells
Which kind of cells do binary fission
Prokaryotic
Describe binary fission
Circular DNA and plasmid(s) replicate
Circular DNA strands move to opposite poles of the cell
Cytoplasm begins to divide
New cell walls begin to form
2 daughter cells produced
How does the rate of binary fission depend on the environment
It can vary. In warm environments with nutrients bacteria can divide very quickly but if conditions become unfavourable the cells will stop dividing and die
What are stem cells
Undifferentiated cells
Where are stem cells used for cloning found
Embryos and bone marrow
What can cloned stem cells do
Differentiate into many different types of human cell
