B9 Cells Flashcards
What are the differences in the structure of plant and animal cells?
Plant:
•cell wall
•chloroplasts
•vacuole
What is a prokaryotic cell?
Bacteria cells
What is a eukaryotic cell?
An animal or plant cell
What do prokaryotic cells have?
Plasmids Slime capsule Flagella Pili Ribosomes
How big are eukaryotic cells compared to prokaryotic cells?
Typically, eukaryotic cells are one order of magnitude bigger than prokaryotic cells
What is diffusion?
The movement of particles from an area of high concentration to an area of low concentration (until equilibrium is reached)
In which states of matter can diffusion occur?
Liquids or gases
What is osmosis?
A special type of diffusion- the movement of water from a dilute to a more concentrated solution through a selectively permeable membrane that allows water to pass through.
What can cause osmosis?
Differences in the concentrations of solutions inside and outside of a cell can cause water to move in or out of the cell by osmosis
What damage can osmosis cause?
It can cause animal cells to be damaged if the concentration outside the cell changes dramatically
What is a key fact about the concentration of water?
If the glucose concentration is high, the water concentration is low
What is a second definition of osmosis?
Movement from a low concentration of solute to a high concentration of solute
What is active transport?
It allows cells to move from an area of low concentration to an area of high concentration (against the concentration gradient)
Why is active transport useful in cells?
Cells can absorb ions from very dilute substances and they can also move substances such as sugars and ions through the cell membrane
What else is needed for active transport?
Energy is needed. The rate of respiration and the rate of active transport are closely linked.
Why is active transport useful in digestion?
Active transport enables sugar used for cell respiration to be absorbed from the gut into the blood
What are the four adaptations for exchanging materials?
1) large surface area
2) thin membrane
3) efficient blood supply
4) being ventilated (in animals)
What is mitosis?
A process involved in cell division that produces two identical cells
What are the five steps in mitosis?
1) the two pairs of chromosomes are copied
2) the chromosomes are forced to the centre by the spindle finders
3) the chromosomes attach to the spindle finders
4) two nuclei are formed
5) the cell splits, creating two identical cells
Why does mitosis need to occur?
To produce extra cells needed for growth and development to replace worn out or damaged cells
How do embryos grow?
Cells split in two every day to form a bundle of cells called an embryo
What is special about embryonic stem cells?
They can become any specialised human cell
What happens after about a week of pregnancy?
The cells stop being the same and begin to differentiate (into different types of cell)
What happens next to the specialised cells?
The cells continue to differentiate until they become specialised cells
