Cell Biology Flashcards
Explain the function of the following:
1) Cell membrane
2) Cytoplasm
3) Nucleus
4) Mitochondria
1) Cell membrane - holds the cell together and controls the movement of the substances in and out of the cell.
2) Cytoplasm - a fluid substance in the cell where most of the chemical reactions happen.
3) Nucleus - contains the genetic material that controls the activities of the cell.
4) Mitochondria - where most of the reactions for aerobic respiration takes place; respiration transfers energy that the cell needs to work.
Explain the function of the following:
1) Cell wall
2) Vacuole
3) Chloroplasts
4) Ribosomes
1) Cell wall - made of cellulose, which supports and strengthens the cell.
2) Vacuole - contains cell sap which provides structure and stores nutrients; weak solution of sugar and salts.
3) Chloroplasts - where photosynthesis occurs and provides food for the plant.
4) Ribosomes - where proteins are made in the cell.
Define Eukaryotic cells; give examples.
Define Prokaryotic cells; describe the structure and give an example.
1) Eukaryotic cells are organisms whose cells are organised into complex structures by internal membranes. Such as animal, plant and algal cells.
2) Prokaryotic cells are organisms without a cell nucleus or any other membrane bound organelles. These have a loop of DNA instead of a nucleus and most are uniceller, only some can be multicellar. Such as bacteria cells.
Describe the structure of a bacteria cell.
- Cell membrane
- Cell wall
- Cytoplasm
- May contain one or more small rings of DNA, Plasmids
- Don’t have a true nucleus but a circular strand of DNA that floats freely in the cytoplasm.
No chloroplasts or mitochondria
Define magnification.
Define resolution.
Magnification enlarges an image to make the object appear bigger.
Resolution determines how clear and detailed the image is as it distinguishes between individual details.
State the formula for magnification.
Image size ÷ real size
What is the symbol for the following measurements and how to convert them?
* Centimetre
* Millimetre
* Micrometre
* Nanometre
- Centimetre - cm (divide by 10)
- Millimetre - mm (divide by 1000)
- Micrometre - μm (divide by 1000)
- Nanometre - nm
What should the observation drawing of what’s seen in the microscope include?
- Drawing must take at least half the space with clear and unbroken lines.
- When drawing cells, the sub-cellular structures should be in proportion
- No colouring or shading
- Must have a title and magnification
- Label the important features using straight and uncorssed lines
What is the symbol for the following measurements and how to convert them?
* Milligrams
* Micrograms
* Nanograms
* Picograms
- Milligrams - mg
- Micrograms - μg
- Nanograms - ng
- Picograms - pg
To go down the list, multiply by 1000 each time.
To go up the list, divide by 1000 each time.
(DM)
How does Cell Differentiation and Specialisation occur?
1) Describe the process. When does it occur and what do cells develop?
2) Cells that differentiate in mature cells, what are they mainly used for? Give an example
3) What are undifferentiated cells called?
1) It’s a process in which a cell changes to become specialised for its job.
As cells change, they develop different sub-cellular structures and turn into different types of cells which allows them to carry out a specific function.
Most differentiation occurs as an organism develops.
2) Cells that differentiate in mature animals are mainly used for repairing and replacing cells, such as skin and blood cells.
3) Some cells are undifferentiated, that are called stem cells.
Specialised Cells
1) Describe the function of sperm cells.
2) State the characteristics and give a reason for it. (3)
1) Specialised for reproduction to get the male DNA to the female DNA.
2) Characteristics:
* long tail and streamlined head to help swim to egg
* lots of mitochondria to provide the energy needed
* carries enzymes in its head to digest through the egg cell membrane
Specialised Cells
1) Describe the function of nerve cells.
2) State the characteristics and give a reason. (2)
1) Specialised for rapid signalling; to carry electrical signals from one part of body to another.
2) Characteristics:
* they are long so they can cover more distance
* branched connections at their ends to connect to other nerve cells and form a network throughout the body.
Specialised Cells
1) Describe the function of muscle cells.
2) State the characteristics and give a reason. (2)
1) Specialised for contraction; to contract quickly.
2) Characteristics:
* they are long so they have space to contract
* contains lots of mitochondria to generate the energy needed.
Specialised Cells
1) Describe the function of root hair cells.
2) State the characteristics and give a reason. (1)
1) Specialised for absorbing water and minerals, on the surface of plant roots.
2) Characteristic:
* grows into long hairs to stick out into the soil which gives plants bigger surface area to absorb nutrients from soil.
Specialised Cells
1) Describe the function of phloem and xylem cells.
2) State the characteristics and give a reason. (3) there’s one for phloem and one for xylem.
1) Specialised for transporting substances (food and water) around the plant through the phloem and xylem tubes.
2) Characteristics:
* the cells are long that join from end to end to form the tubes
* xylem cells are hollow in centre
* phloem cells have very few sub-cellular structures so that nutrients can flow through them.
