Topic 1- Cell biology Flashcards
What cells are eukaryotic?
Animal and plant cells
What do plant and animal cells have?
Cell membrane Cytoplasm Nucleus containing DNA
What cells are prokaryotic?
Bacterial cells
What do Bacterial cells have?
Cell wall Cell membrane Cytoplasm Single circular strand of DNA and plasmids
Define plasmids
Small rings of DNA found in the cytoplasm
What are organelles?
Structures in a cell that have different functions
Define nucleus
Contains DNA coding for a particular protein needed to build new cells. Enclosed in a nuclear membrane
Define cytoplasm
Liquid substance in which chemical reactions occur. Contains enzymes Organelles are found in it
Define enzymes
Biological catalysts
Define cell membrane
Controls what enters and leave the cell
Define mitochondria
Where aerobic respiration reactions occur, providing energy for the cell
Define ribosomes
Where protein synthesis occurs Found on a structure called the rough endoplasmic reticulum
Define chloroplasts
Where photosynthesis takes place, providing food for the plant Contains chlorophyll pigment which harvest the light needed for photosynthesis
Define permanent vacuole
Contains cell sap Found within the cytoplasm Improves cell’s rigidity
Define cell wall
Made from cellulose Provides strength to the cell
Define differentiation
A process that involves the cell gaining new sub-cellular structures in order for it to be suited to its role.
Define sperm cells
Specialised go carry the male’s DNA to the egg cell (ovum) for successful reproduction
How are sperm cells specialised?
Streamlined head and long tail to aid swimming Many mitochondria (where respiration happens) which supply the energy to allow the cell to move Acrosome (top of the head) has digestive enzymes which breaks outer layers of membrane of the egg cell
Define nerve cells
Specialised go transmit electrical signals quickly from one place in the body to another
How are nerve cells specialised
Axon is long, enabling the impulses to be carried along long distances Having lots of extensions from the cell body (called dendrites) means branched connections can form it’s other nerve cells The nerve ending have many mitochondria which supply the energy to make special transmitter chemicals called neurotransmitters. These allow the impulse to be passed from one cell to another
Define muscle cells
Specialised to contract quickly to move bones (striated muscles) or simply to squeeze, therefore causing movement
How are muscle cells specialised?
Special proteins slide over each other, causing the muscle to contract Lots of mitochondria to provide energy from respiration for contraction They can store a chemical called glycogen that is used in respiration by mitochondria
How are root hair cells specialised?
Specialised to take up water by osmosis and mineral ions by active transport from the soil as they are found in the tips of roots. Have a large surface area due to root hairs, meaning more water can move in. The large permanent vacuole affects the speed of movement of water from the soil to the cell. Mitochondria to provide energy from respiration for the active transport of mineral ions from the root hair cell
How are xylem cells specialised?
Specialised to transport water and mineral ions up from the plant to the roots of the shoots Upon formation, a Chemical called lignin is deposited which caused the cells to die. They become hollow and are joined end-to-end to form a continuous tube so water and mineral ions can move through Lignin is deposited in spirals which helps the cells withstand the pressure from the movement or water
How is phloem cells specialised?
Specialised to carry out products of photosynthesis (food) to all parts of the plants Cell walls of each cell from structures called sieve plates when they break down, allowing the movement of substances from cell to cell Despite losing many sub-cellular structures, the energy these cells need to be alive is supplied by the mitochondria of the companion cells .
Define mitosis
Process that involves a cell dividing to produce 2 identical cells.
When does cell division mostly only happens in mature animals?
Only happens to repair or replace damaged cells, as they undergo little growth.
When does cell division mostly happen in plants?
Many type of cells retain the ability to differentiate throughout life. They only differentiate when they reach their final position in the plant, but they can still re-differentiate when it is moved to another position.
Define magnification
Enlarge the image
Advantages of light microscope
Has two lenses, an objective and eyepiece. Have a maximum magnification of x2000 and a resolving power of 200nm. Used to view tissues, cells and large sub-cellular structures.
What does the objective lenses produce ?
Magnified image, which is the magnified and directed into the eye by the eyepiece lense. Usually illuminated from underneath
Advantages of electron microscope
Enables scientists to view deep inside sub-cellular structures. Have a magnification of up to X2,000,000 and resolving power of 10nm (SEM) and 0.2nm (TEM)
What are the 2 types of electron microscope?
Scanning electron microscope that creates 3D images Transmission electron microscope which creates 2D images detailing organelles
Define mitosis
Process that involves a cell dividing to produce 2 identical cells.
When does cell division mostly only happens in mature animals?
Only happens to repair or replace damaged cells, as they undergo little growth.
When does cell division mostly happen in plants?
Many type of cells retain the ability to differentiate throughout life. They only differentiate when they reach their final position in the plant, but they can still re-differentiate when it is moved to another position.
Define magnification
Enlarge the image
Advantages of light microscope
Has two lenses, an objective and eyepiece. Have a maximum magnification of x2000 and a resolving power of 200nm. Used to view tissues, cells and large sub-cellular structures.
What does the objective lenses produce ?
Magnified image, which is the magnified and directed into the eye by the eyepiece lense. Usually illuminated from underneath
Advantages of electron microscope
Enables scientists to view deep inside sub-cellular structures. Have a magnification of up to X2,000,000 and resolving power of 10nm (SEM) and 0.2nm (TEM)
What are the 2 types of electron microscope?
Scanning electron microscope that creates 3D images Transmission electron microscope which creates 2D images detailing organelles
