Topic 2A: Cell Structure and Division Flashcards
Describe a lysosome
A round organelle surrounded by a membrane, type of golgi vesicle
What’s the function of a lysosome?
Contains digestive enzymes (lysozymes), used to digest invading cells or to break down worn out components
Describe a ribosome
A very small organelle that floats free in the cytoplasm or attached to rough ER, made of proteins/RNA
What’s the function of ribosomes?
Where proteins are made-protein synthesis
Describe rough ER
A system of membranes enclosing a fluid-filled space, covered in ribosomes
What’s the function of rough ER?
Folds and processes proteins that have been made in the ribosomes
Describe smooth ER
A system of membranes like RER, but without ribosomes
What’s the function of smooth ER?
Synthesis’s and processes lipids
Describe cell walls
A rigid structure surrounding cells in plants, algae and fungi mainly made of the carbs and cellulose
What’s the function of cell walls?
Supports cells and prevents them from changing shape
Describe the vacuole
Membrane-bound organelle found in the cytoplasm, contains cell sap (surrounding membrane is tonoplast)
What’s the function of the vacuole?
Helps maintain pressure inside the cells and keep it rigid (stops plant wilting)
How do Prokaryotic cells replicate?
Binary Fission
Explain binary fission
Step 1) Circular DNA replicates main DNA once, plasmids divide multiple times
Step 2) Cells get bigger the DNA loops move to opposite poles.
Step 3) Cytoplasm divides
Step 4) 2 daughter cells are produced, each cell has one circular DNA but multiple plasmids
Viruses aren’t cells, what are they?
Acellular, nucleic acids surrounding by a protein coat
What do viruses need to re-produce?
Host-cell
Once the virus is attached to the host-cell what does it do?
Inject their DNA/RNA into the host cell
What’s the magnification equation?
Magnification= size of image/real object size
How do you get from micrometers to nanometers?
X1000
How do you get from nanometers to micrometers?
/1000
What are microscope artifacts?
Things you see down a microscope that aren’t part of the cell, e.g fingerprints/bubbles
What’s a TEM microscope?
TEM use electromagnets to focus a beam of electrons this is transmitted through the specimen. Denser parts of the specimen absorb more electrons appearing darker
What’s a SEM microscope?
SEM’s scan a beam of electrons across a specimen. Knocking off electrons from the specimen (3D)
Describe the chloroplast
Small flattened structure found in plant cells and algal cells, double membrane, inside also thylakoid membranes, forming grana