B2 1 Cells And Tissues Flashcards
What is the cytoplasm?
A liquid gel where most of the chemical reactions needed for life take place.
What does the nucleus do?
The nucleus controls all the activities of the cell. It contains the genes on the chromosomes. They carry the instructions for making new cells or new organisms.
What does the cell membrane do?
The cell membrane controls the passage of substances into and out of the cell.
What is the mitochondria?
Structures in the cytoplasm where oxygen is used and most of the energy is released during respiration.
What do ribosomes do?
This is where protein synthesis takes place. All the proteins needed in the cell are made here.
What are chloroplasts?
Found in the green parts of the plant and contains a substance called chlorophyll. The chlorophyll absorbs light energy to make food by photosynthesis.
What does a cell wall do?
A cell wall is made of cellulose which strengthens the cell and gives it support.
What is a permanent vacuole?
A space in the cytoplasm filled with cell sap. This is important for keeping cells rigid to support the plant.
What does a bacterial cell consist of?
Cytoplasm and a membrane surrounded by a cell wall. The genes aren’t in the distinct nucleus. Many also have plasmids which are small circular bits of DNA. The flagella is a long protein strand which propels the bacteria.
What is yeast?
A single celled organism with each cell consisting of a nucleus, cytoplasm and a membrane surrounded by a cell wall.
Facts about yeast
Yeasts reproduce by asexual budding which means a new yeast cell grows out from the original cell. Yeasts are specialised to survive long periods without oxygen. Yeasts can respire aerobically and anaerobically. Fermentation occurs when yeasts respire anaerobically.
Specialised cells
Specialised cells may be used to carry out a particular task.
Examples of specialised cells
Fat cells- small cytoplasm and large amounts of fat. Few mitochondria as the cell doesn’t need lots of energy. They can expand. Root hair cells- root hairs increase the surface area for water to move into the cell. The root hair cells have a large permanent vacuole that speeds up the movement of water by osmosis from the soil across the root hair cell.
What is diffusion?
Diffusion is the spreading out of the particles of a gas or of any substance in a solution from an area of high concentration to an area of a lower concentration.
Rates of diffusion
If there is a big difference in concentration between two areas, diffusion will take place quickly. The bigger the difference the steeper the concentration gradient. Temperature- An increase in temperature means the particles in a gas or solution move quickly. Surface area- an increase in surface area means there is more room for diffusion to take place.
Animal Cell
Plant Cell
