Cell Biology Flashcards
How are Xylem and Phloem cells specialised?
There function is to carry water and minerals through the plant. They both form hollow tubes, though Xylem form these out of dead tissue, whereas phloem form theas out of living tissue.
What is resolution?
The shortest between two objects before they are seen as one.
Describe a light microscope in these factors- Radiation used- Max magnification- resolution- Size of Microscope- Cost-
- Light rays
- 1500 times
- 200nm
- small and portable
- £100 for a school one
Describe these features of an electron microscope- Radiation used- Max magnification- Resolution- Size of Microscope- Cost-
- Electron beams
- 2 000 000 times
- 0.2nm
- Very large and not portable
- Several £100 000 to a million.
What can we see in light microscopes compared to electron microscopes.
Using light microscopes, we can see structures like nuclei and mitochondria. Can let us see ribosomes and golgi apparatus as well as internal structures of organelles. This is because they have a higher magnification and resolution.
What is the equation for magnification? Think MIRACLE!
Magnification- image size divided by size of the real object.
How are root hair cells specialised?
They have a larger surface area to increase gas exchange, They also have no chloroplasts as they don’t photosynthesize.
What are meristems?
Unspecialised stem cells in plants.
What are the advantages of embryonic stem cells?
Each stem cell divides every 30 minutes. There is a low chance of a patients immune system rejecting the cells. They also differentiate into more types of cells than adult.
What are some advantages of Adult stem cells?
They cost less than embryonic stem cells. There are less ethical issues and is considered more safe.
What is therapeutic cloning?
A process that produces an embryo with the same genetic information as the patient. This means they will not be rejected by the patient’s immune system. However, it is hard to find stem cell donors, they also need to be taken from birth. Mutations can occur and behave like cancer cells.
Are prokaryotic cells more simple or complex than eukaryotic cells.
Prokaryotes are more simple cells, they do not have a nucleus, instead they have a circular strand of DNA and plasmids around that. They have cytoplasm, cell membrane, a cell wall and cytoplasm.
Describe how you would view epidermal tissue under a microscope.
Add a drop of water to the middle of a slide, get some epidermal tissue from the subject and place on top of the water. Add iodine solution to stain. Then place a cover slip on top, whilst trying to trap as few air bubbles as possible.
What is inside the nucleus?
Inside the nucleus are lots of singular chromosomes that contain coiled up DNA. This DNA can be split up into genes. Genes are small sections of DNA, that contain codes for specific proteins.
How is size of organisms related to SA/V ratios.
Smaller animals tend to have larger SA/V ratios, which means they lose more heat. Animals in cold temperatures will often have a smaller SA/V ratio to conserve heat.
