Cell Biology Flashcards
What are cells?
Cells are basic units of life.
What are the four types of cell?
Animal, plant, fungal and bacterial
Name all the organelles in an animal cell.
- ribosomes
- cell membrane
- mitochondria
- cytoplasm
- nucleus
Name all the organelles in a plant cell.
- chloroplasts
- cell membrane
- cell wall (cellulose)
- cytoplasm
- mitochondria
- vacuole
- ribosomes
- nucleus
Name all the organelles in a fungal cell.
- cytoplasm
- cell wall (no cellulose)
- cell membrane
- vacuole
- mitochondria
- ribosomes
- nucleus
Name all the organelles in a bacterial cell.
- plasmid
- bacterial chromosome
- cell wall
- cell membrane
- cytoplasm
- ribosomes
- flagellum
What is the function of the nucleus?
Controls cell activities.
What is the function of the cell membrane?
Controls movement of substances in and out of the cell.
What is the function of the cell wall?
Supports the cell, gives it a rigid structure.
What is the function of the cytoplasm?
Contains organelles and is the site of chemical reactions.
What is the function of the ribosome?
Site of protein synthesis.
What is the function of the mitochondria?
Site of aerobic respiration.
What is the function of the chloroplast?
Site of photosynthesis.
What is the function of the vacuole?
Stores water, sugar and salt as cell sap.
What is the function of the plasmid?
Circular rings of DNA that contain additional genes which are beneficial to the cell.
Is the cell membrane selectively permeable?
Yes, it only allows small and soluble molecules to cross.
What is the cell membrane made up of?
Proteins and phospholipids.
What is diffusion?
The movement of molecules down a concentration gradient from a higher to a lower concentration.
Is diffusion a passive or active process?
Passive, which means it does not require energy.
What is a concentration gradient?
It is the difference between a high and low concentration.
Why is diffusion important?
- To gain the raw materials for respiration
—> oxygen and food (e.g glucose) - To remove waste products
—> carbon dioxide, urea
What is the diffusion of water called?
Osmosis.
What is osmosis?
Osmosis is the movement of water molecules from a higher water concentration to a lower water concentration through a selectively permeable membrane.
Is osmosis a passive or active process?
A passive process, this means it does not require energy.
What happens to an animal cell placed in pure water?
Water enters the cell by osmosis down a water concentration gradient, the animal cell bursts.
What happens to an animal cell when it’s placed in a dilute sugar/salt solution?
As there is no difference in the water concentration inside and outside the cell, no change occurs.
What happens to an animal cell placed in a concentrated sugar/salt solution?
Water leaves by osmosis down a water concentration gradient, the animal cell shrinks.
What happens to a plant cell that is placed in pure water?
Water enters by osmosis causing the cell to swell, the cell wall prevents it from bursting. The cell is now described as turgid.
What happens to a plant cell placed in a dilute sugar/salt solution?
As there is no difference in the water concentration, no change occurs.
What happens to a plant cell placed in a concentrated sugar/salt solution?
Water leaves by osmosis. This causes the vacuole to shrink away from the cell wall. The cell is now described as plasmolysed, the tissue is described as flaccid.
What is active transport?
Active transport is the movement of molecules across a cell membrane from a low to a high concentration i.e against the concentration gradient
Does active transport require energy?
Yes, as energy is needed to move molecules against the concentration gradient.
What is DNA?
DNA is a molecules which carries genetic information.
