cell biology Flashcards
What are eukaryotic cells?
Eukaryotic cells contain their genetic material enclosed in a nucleus. Larger and more complex (10-100 micrometres)
What are prokaryotic cells?
Prokaryotic cells don’t have their genetic material enclosed in a nucleus. Smaller but complex (1-10 micrometres)
Examples of prokaryotic and eukaryotic cells
Prokaryotic - bacteria
Eukaryotic - animal and plant cells
What is one order of magnitude?
An order of magnitude is x10.
What is the function of the nucleus?
The nucleus contains genetic information and controls the activities in the cell.
What is the function of the cell membrane?
The cell membrane holds the cell together and controls what goes in or out.
What is the function of the cytoplasm?
The cytoplasm is where chemical reactions take place and contains enzymes.
What is the function of ribosomes?
Ribosomes are where protein synthesis takes place.
What is the function of the mitochondria?
The mitochondria is where most reactions for aerobic respiration take place, which transfers energy that the cell needs.
What is the function of the cell wall?
The cell wall is only in plant cells for strength and support.
What is the function of the vacuole?
The vacuole is only in plant cells and contains cell sap (a weak solution of sugar and salts) to keep the cell rigid.
What is the function of the chloroplast?
The chloroplast is only in plant cells and is where photosynthesis takes place. It contains green chlorophyll which absorbs light.
What does it mean if a cell is specialised?
Specialisation means that a cell has differentiated to carry out a particular function.
How is a sperm cell adapted for its function?
sperm cell:
- tail and streamlined head to move into egg
- lots of mitochondria to provide energy
- enzymes in head to digest egg membrane
- large nucleus for more DNA
How is a nerve cell adapted for its function?
nerve cell:
- long axon carries electrical impulses
- myelin coating insulates to speed up impulses
- synapses to allow passing of impulses
- dendrites increase surface area so other cells connect easily
How is a muscle cell adapted for its function?
muscle cell:
- protein fibres which can change their length
- lots of mitochondria to provide energy
- they work together as a tissue
How is a root hair cell adapted for its function?
root hair cell:
- small hairs increase surface area, so more effective at taking up water
- don’t contain chloroplasts as underground
- large vacuole speeds up water movement
How is a xylem cell adapted for its function?
xylem cell: (carry water and minerals from roots to leaves)
- very thick walls with lignin for support
- hollow tube so water and minerals can flow through
- no nucleus, cytoplasm, vacuole or chloroplast
How is a phloem cell adapted for its function?
phloem cell: (carry dissolves sugars around plant)
- companion cells provide energy
- phloem vessel cells have no nucleus and limited cytoplasm and mitochondria to allow easier flow
What are the differences between a light and electron microscope?
light - colour, easier to carry, longer wave length
electron - more magnification and resolution
Describe bacterial division.
binary fission:
1) DNA and plasmids replicate
2) they move to opposite sides
3) cytoplasm divides and new cell wall forms
Describe mitosis.
mitosis (cell division):
1) DNA replicates so two copies of each chromosome
2) the cell grows and copies some subcellular structures
3) one set of chromosomes is pulled to each end of the cell
4) the nucleus divides
5) cytoplasm and cell membranes divide to form identical cells
What is a stem cell?
A stem cell is an undifferentiated cell.
What is the difference between embryonic and adult stem cells?
Embryonic stem cells have the potential to form almost any cell, but adult stem cells cannot differentiate.
