Cell Biology Flashcards
What is the job of a nucleus?
Controls cell activities and contains the genetic material
What is the function of the cytoplasm?
Where most of the chemical reactions take place.
What is the function of the cell membrane?
Controls the passage of substances in and out of the cell.
What type of respiration takes place in the mitochondria?
Aerobic respiration takes place in the mitochondria.
What is the function of ribosomes?
To synthesize proteins.
Why do plant cells have a cell wall?
To strengthen the cell.
Why do plant cells contain a vacuole?
To contain cell sap which supports the plant.
Why do plants need chloroplast?
To absorb light to make glucose by photosynthesis
Which cells are eukaryotic?
Plant, animal and fungal cells
Which cells are prokaryotic?
Bacterial cells.
What does and what doesn’t a prokaryotic cell contain?
It contains small rings of DNA called plasmids and doesn’t contain mitochondria or chloroplast.
What is in a bacterial cell?
Plasmid, cytoplasm, cell wall, chromosomal DNA, Flagella.
What do plant cells contain that animal cells do not?
Cell wall, chloroplast, and a vacuole.
What are the steps for the required practical: Use a light microscope to observe a section of plant and animal cells?
1) Place a tissue sample on a microscope slide.
2) Add a few drops of sustainable stain.
3) Lower a coverslip onto the tissue.
4) Place the slide on the stage and focus using low power.
5) Change to high power and refocus.
6) Draw any types of cells that can be seen.
7) Add a scale line to the diagram.
What is the equation to work out magnification?
Size of image / Size of real object.
How many cm, mm, micrometres and nanometres are there in 1 meter?
CM=100
MM=1,000
MICROMETER=1,000,000
NANOMETER=1,000,000,000
What is a light microscope?
Developed in the late 16th century and has a greater resolution than the human eye. Also allowed them to see the animal, plant, and bacteria cells.
What is an electron microscope?
First used in 1933. Gives more resolution and cells can be seen in finer detail.
What type of simple cell division does bacteria use?
Binary fission
What type of simple cell division does bacteria use?
Binary fission
What is a culture?
Bacteria that can be grown in a nutrient broth or colonies on agar.
What is the technique to make uncontaminated cultures?
1) Petri dish and agar are sterilised to kill unwanted microorganisms.
2) An inoculating loop is sterilised by passing it through a flame.
3) The cooled inoculating loop is used to transfer bacteria to the agar.
4) Lid must be quickly removed and replaced with tape to stop it from coming off.
5)Store the dish upside down to stop condensation from dripping on the agar surface.
What is the cultures techniques called?
Aseptic technique
What does the nucleus of a cell contain?
Chromosomes made of DNA
How many pairs of chromosomes do humans have?
23 pairs.
What happens during mitosis?
1) One set of chromosomes is pulled to each end of the cell.
2) The nucleus divides.
3) The cytoplasm and cell membranes divide to form 2 identical cells.
What is an undifferentiated cell and what is it called?
A cell that has not become specialised yet. It is called a stem cell.
Where are stem cells found?
They are found in human embryos, in the umbilical cord of a newborn baby.
Where are adult stems found?
In some organs and tissues.
What is therapeutic cloning?
When a cloned embryo of the patient is used as a source of stem cells.
Why are some people concerned about cloned embryos?
There might be risks or religious and ethical reasons.
Where are the stem cells in plants found?
In the meristem.
What is diffusion?
Diffusion is the net movement of particles from a high concentration to a low concentration.
What diffuses during gas exchange in lungs., gills and plant leaves?
Oxygen and carbon dioxide.
What are the factors that affect the rate of diffusion?
The concentration gradient, the temperature and the surface area of the membrane.
What is osmosis?
Osmosis is the diffusion of water from a dilute solution to a concentrated solution through a partially permeable membrane.
What is the method for the effect of different concentration sugar solutions on plant tissues and what is the result?
1) Cut some cylinders of potato tissue and measure their mass.
2) Place the cylinders in different concentrations of sugar solution.
3) After about 30 minutes remove the cylinders and measure their mass again.
If the cylinder changes in mass they have gained or lost weight via osmosis.
What are the IV, DV and CV of the practical : The effect of different concentration sugar solutions on plant tissues
IV= The concentration of sugar solution.
DV= The mass of the potato.
CV= The temperature, the time and the volume of solution.
What is Active Transport?
Active Transport moves substances against a concentration gradient, from a low concentration to a high concentration.
What does Active Transport allow?
Allows mineral ions to be absorbed into plant root hairs from very dilute solutions in the soil. Also allows sugar molecules to be absorbed from the gut to the blood.
