TOPIC B1 Cell Biology Flashcards
All living things are made up of….
cells.
Give 2 facts about Eukaryotic cells:
- They are complex.- All animal and plant cells are Eukoryotic.
List the 5 things you will see in an Animal Cell:
1 - nucleus.2 - cytoplasm3 - cell membrane4 - mitochondria5 - ribosomes
What is the role of the Nucleus?
Contains genetic material and control what the cell does.
What is the role of Cytoplasm?
It is where most chemical reactions happen. A gel-like substance that contains enyzmes.
What is the role of Mitochondria?
It is where most aerobic respiration reactions happens. Respiration transfers energy that the cell needs to work.
What is the role of the Cell Membrane?
Holds the cell together and controls what goes in and out.
What is the role of Ribosomes?
This is where proteins are made in the cell.
Plants have all the bits of an animal cell plus 3 extra things:
- cell wall- permanent vacuole- chloroplasts
What is the role of a Cell Wall?
It supports the plant cell and strengthens it. MADE OF CELLULOSE.
What is the role of the Permanent Vacuole?
Contains cell sap, a weak solution of sugar and salts.
What is the role of Chloroplasts?
It is where photosynthesis happens. Photosynthesis makes food for the plant. Contains a green substance called chlorophyll which absorbs light for Photosynthesis.
Prokaryotic cells are smaller and simpler, an example is….
A bacterial cell.
Do Bacterial Cells have a Nucleus?
NO. They have a single circular strand of DNA that floats freely in the cytoplasm.
What are Plasmids in a Bacterial Cell?
Small rings of extra DNA.
What can we use a Light microscope for?
To look at cells because they allow us to see individual cells and large subcellular structures (like the nucleus)
Why are Electron microscopes better than Light microscope? (2)
They have a higher resolution so we can see things in more detail. (sharper image)They have a higher magnification so we can see really small things like ribosomes and plasmids or small things in detail like the internal structure of mitochondria.
What is Magnification?
How many times bigger the image is than the real thing.
Formula for Magnification:
MAGNIFICATION = IMAGE SIZE DIVIDED BY REAL SIZE.
How to prepare an onion slide ready for the microscope ( 6 )
1) Add a drop of water to the middle of a clean slide.
2) Cut up and onion and take off one layer.
3) Use tweezers to peel off some epidermal tissue (the clear skin) from the bottom of the layer.
4) Using the tweezers place the skin into the water on the slide.
5) Add a drop of iodine solution.
6) Place a cover slip on top, try not to get any air bubbles - they will obstruct your view of the specimen.
Iodine Solution is a stain, why are stains good?
They make different parts of a cell easier to see.
How to use a light microscope to look at your slide ( 6 )
1) Clip the slide onto the stage.
2) Select the objective lense with the lowest magnification.
3) Use the course adjustment knob to move the stage up to just below the objective lens.
4) Look in the eyepiece. Move the stage downwards till the image is roughly focused.
5) Move the fine adjustment knob until you get a clear image of what’s on the slide.
6) If you want a bigger image use an objective lens with a higher magnification and refocus.
How to draw your observations (6)
1) Use a pencil with a sharp point.2) Take up at least half of the space avaliable with clear, unbroken lines.
3) NO SHADING NO COLOURING.
4) If you are drawing cells, the subcellular structures should be drawn in proportion.
5) Include a title and write the magnification that it was observed under.
6) Label the important features using straight, uncrossed lines.
What are Specialised Cells?
Cells that carry out a specific function.
What is the process called when a cell changes to become specialised for its job?
Differentiation.
What do cells develop as they change?
Different subcellular structures and turn into different types of cells.
When can an animal cell differintiate?
At an early stage of the animal’s life.
When can a plant cell differentiate?
Anytime.
What are cells that differentiate in adult animals mainly used for?
Repairing and replacing cells such as skin or blood cells.
What are undifferentiated cells called?
Stem cells.
What function do Sperm Cells carry out?
They take the male DNA to the egg.
Give 3 ways a Sperm Cell is adapted to it’s job:
1) It has a long tail and streamlined head to help it swim to the egg.2) packed with mitochondria to provide energy for swimming.3) It has enzymes in its head to digest through the egg cell membrane.
What function do Nerve Cells carry out?
They carry electrical signals from one part of the body to another.
Give 2 ways Nerve Cells are adapted to their job:
1) They are long to cover more distance in the body.
2) They have branches at the end to connect to other nerve cells and form a network through the body.
What function do Muscle Cells carry out?
To contract quickly.
Give 2 ways Muscle Cells are adapted to their job:
1) They are long so they have space to contract.
2) Lots of mitochondria to provide energy for contracting.
What function do Root Hair Cells carry out?
They are cells on the surface of plant roots - absoring water and minerals.
Give 2 ways Root Hair Cells are adapted to their job:
1) They grow into long “hairs” that stick out into soil.2) This gives the plant a big surface area for absorbing water and mineral ions from the soil.
What function do Phloem Cells carry out:
They transport food to the plant.
What function do Xylem Cells carry out:
They transport water to the plant.
How are Xylem and Phloem Cells adapted to their function? (3)
1) they form tubes.
2) to form the tubes the cells are long and joined end to end.
3) Xylem cells are hollow and Phloem have very few subcellular structures. LOTS OF SPACE for things to flow through them.
Where do Chromosomes live?
In the Nucleus.
Chromosomes contain…..
Genetic Information.
What are Chromosomes?
Coiled up lengths of DNA molecules.
Different genes control……..
the development of different characteristics e.g. hair colour.
How many pairs of chromosomes are there in your body?
23.One from the organism’s mother and one from the father.
What is Mitosis?
When the body cells in multicellular organisms divide to produce new cells as part of a series of stages called the cell cycle. Mitosis is the stage when the cell divides.