Biology- Cells Flashcards
What does the cell membrane do?
Controls what enters and leaves the cell.
What does the cytoplasm do?
Where chemical reactions occur.
What does the mitochondria do?
Where chemical reactions for cell respiration takes place.
What does the nucleus do?
The control centre of the cell.
What does a cellulose cell wall do?
Prevents cell from bursting when taking in water.
What does the vacuole do?
Contains Sap which provides support and makes the cell rigid.
What do chloroplasts do?
Contains chlorophyll which makes the cell food during photosynthesis.
What does DNA do?
It’s in the form of circular chromosomes.
Parts of a microscope.
1.Eyepiece Lens
2.Eyepiece
3.Spine
4.Clips
5.Fine 6.Focusing 7.Knob
8.Course Focusing Knob
9.Objective Lens
10.Stage
11.Light Source
Prep an onion slide.
- Peel thin layer of onion
- Place on microscope slide
- Add iodine
- Lower coverslip
Prep a cheek slide.
- Swab Cheek
- Smear on microscope slide
- Add methylene blue
- Lower coverslip
Pros of an electron microscope.
- Better resolution
- Higher magnification
Cons of an electron microscope.
- Large
- Needs a special room
- Complex prep
- Kills tissue cell
- Expensive
What is diffusion?
The random movement of a substance from an area of high concentration to a lower concentration.
What is concentration gradient?
The difference in concentration between high and low areas.
Temperature and concentration gradient
Higher the temperature, more kinetic energy of molecules making them move faster & increasing the rate of diffusion.
Surface area & concentration gradient
The larger the area over which diffusion takes place the faster diffusion occurs.
Palisade Cell
Lots of chloroplasts
Ciliated Epithelial Cell
Waft to and fro to remove bacteria from the airway
Neurone
Long and thin with many extensions
Pros of embryonic stem cells
1.Can form any cell type
2. Grow rapidly
3. Easy to culture
Ethical issues
- Leads to designer babies
- Use of embryo in this way is considered murder
- Human rights of embryo are ignored
Adult stem cells cons
- Can only be used for certain cell types
- Don’t grow as fast
- Not as easy to culture
Medicine
- Used to treat Parkinson’s disease
- Build new bone tissue and cartilage
- Produce new immune cells to fight infection
Leukaemia
1.Chemo/radio destroys cancerous blood cells
2. Bone marrow stops producing blood cells
3. Transplant of bone marrow containing healthy stem cells from a matching donor
4. Donors cells multiply and produce healthy blood cells in the patient
Risks- leukaemia
- Chemo/radio destroys white blood cells before transplant leaving patient with no immune system-> prone to infection
- Stem cells may divide in an uncontrolled way and produce tumours
