Foundation: B1 - Cell Biology Flashcards
What is a eukaryotic cell?
A cell that has its genetic material in a nucleus, eg. an animal cell.
What is a prokaryotic cell?
A cell taht has a single loop of DNA in the cytoplasm, not in a nucleus, eg. a bacterial cell.
What is the function of the nucleus?
Contains genetic information (DNA).
What is the function of the cytoplasm?
Where chemical reactions take place in the cell.
What is the function of the cell membrane?
Controls what enters & exits the cell.
What is the function of the mitochondria?
Where aerobic respiration occurs.
What is the function of the ribosomes?
Make proteins
What is the function of the chloroplasts?
Where photosynthesis occurs
What is the function of the vacuole?
Stores sap
What is the function of the cell wall?
Strengthen the cell
What is a cell wall made of?
Cellulose
Which cell parts are found only in plants?
Chloroplasts, cell wall, vacuole
How is a muscle cell specialised?
Has lots of mitochondria to do lots of respriation to supply lots of energy to the cell.
How is a sperm cell specialised?
Has a tail (flagellum) to swim to the egg, lots of mitochondria to do lots of respiration to supply lots of energy for swimming.
How is a nerve cell specialised?
Has a very long body to carry electrical impluses throughout the body, can make lots of connections with other nerve cells.
How is a root hair cell specialised?
Has a large surface area for efficient absorption of substances from the soil
How is xylem specialised?
Dead cells with no top or bottom to form a continuous column to transport water and support the plant.
How is phloem specialised?
Sieve plates at the ends of cells allow substances to travel through the plant.
What is cell differentiation?
When an unspecialised cell becomes specialised.
What type of microscope is used in schools?
Light microscope
What type of microscope has very high magnification and resolution?
Electron microscope
What is the equation to calculate magnification?
Magnification = image size / actual size
What is mitosis?
How body cells divide.
What are the stages of the cell cycle?
- The cell grows, makes more organelles and replicates DNA so there are two copies of each chromosome.
- One set of chromosomes is pulled to each end of the cell and the nucleus divides.
- The cytoplasm and cell membrane divides to form two idientical cells.
Why does mitosis occur?
For growth and repair.
What is a stem cell?
An undifferentiated cell of an organism that cen differentiate into many different types of cells.
What is the difference between embryonic and adult stem cells?
Adult stem cells can differentiated into some types of cells, embryonic stem cells can differentiate into most types of cells.
What is a meristem cell?
A stem cell found in the roots and shoots of plants.
What is diffusion?
The movement of particles from an area of high concentration to an area of low concentraion. The particles move down a concentration gradient. This is a passive process so it does not use any energy.
What is osmosis?
The movement of water particles from a dilute soltion to a more concentrated solution, through a partially permeable membrane. This is passive process so it does not require energy.
What is active transport?
The movemebt of particles from an area of low concentration to an area of high concentration. The particles move against a concentration gradient. This is an active process so it requires energy.
What factors affect the rate of diffusion?
The difference in concentrations (concentration gradient)
The temperature
The surface area of the membrane
Where does diffusion occur in plants and animals?
Oxygen diffuses from the alveoli in the lungs into the red blood cells.
Carbon dioxide diffuses from the atmosphere into leaves.
Glucose diffuses from the small intestine into the blood.
Where does active transport occur in plants and animals?
Glucose is absorbed from the small intestine into the blood at the end of the small intestine by active transport.
Some mineral ions are absorbed from the soil into root hair cells by active transport.
How are the lungs and small intestine adapted for efficient diffusion?
Large surface area
Thin membrane
Efficient blood supply