Topic 1 - Cell biology Flashcards
List the cell parts which bacteria have.
- cytoplasm
- cell membrane
- Loop of DNA
- Plasmid
- Cell wall
- flaggelum
What cell parts do animal cells have?
- Nucleus
- cytoplasm
- cell membrane
- mitochondria
- ribosomes
What cell parts do plant cells have?
- nucleus
- cytoplasm
- cell membrane
- mitochondria
- ribosomes
- cell wall
- chloroplasts
- vacuole
What are the adaptations of sperm cells?
- Streamlines
- Long tail to help swim
- Acrosome in head containing enzymes
- large number of mitochondria
What are the adaptations of nerve cells?
- Long to carry signals
- Branched connections to connect to other nerves
- insulating sheath to enhance transmission
What are the adaptations of muscle cells?
- contain a large number of mitochondria
- Long, so there is space to contract.
- Can store glycogen that is used in respiration
What are the adaptations of root hair cells?
- hair like projections to increase surface area.
What are the adaptations of xylem?
- made of dead tissue
- long cells with wall toughened with lignin
- water and mineral flow from roots to leaves
What are the adaptations of phloem?
- made of living tissue
- cells have end plates with holes in them
- glucose solution moves from the leaves to growth and storage tissues
What is cell differentitation?
Cell differentiation is when a cell changes and becomes specialised.
When do animal cells differentiate?
In early stages of development
What is the resolution of a light microscope?
200nm
What is the resolution of an electron microscope?
0.2nm
How do you use a microscope?
- Place a thin section of the specimen onto a slide
- Stain the specimen if needed
- Lower the cover slip onto the specimen
- Switch on the light and place slide on stage
- Use the lowest objective lens and turn the rough focusing wheel to move the lens closer to the slide
- Adjust the fine focusing wheel until you see a clear image
- repeat step 5-6 to increase magnification.
What is the cell cycle?
- Growth - the cell grows and increases the number of subcellular structures.
- DNA synthesis - The DNA replicates to form two copies of each chromosome
- Mitosis - One set of chromosomes is pulled to each end of the cell and the nucleus divides. Then the cytoplasm and cell membranes divide to form two daughter cell which are identical to the parent cell.
What are stem cells?
Stem cells are undifferentiated cells whithin an organism. They can turn into any cell in an organism
What are the 2 different types of human stem cells?
- Embryonic stem cells
- Adult stem cells
What are the advantages of embryonic stem cells?
- Easy to collect and produce in a lab.
- People do not need any operations to be collect embryos
- Embryo stem cells can be turned into any cells
What are the disadvantages of embryonic stem cells.
- embryo is the beginning of life being destroyed
- Stem cell research is expensive
What are the advantages of adult stem cells?
- Stem cells taken from the adult it will be used on will prevent rejection
- They can be harvested without taking life
What are the disadvantages of adult stem cells.
- It’s expensive
- Harder to collect as people require operations
- They can only be turned into certain cells.
Where are adult stem cells found?
Bone marrow
What is therapeutic cloning?
Therapeutic cloning is when you produce an embryo with the same genes as the patient.
What is the definition of diffusion?
- The spreading out of particles
- In a liquid
- Resulting in a net movement form an area of high concentration to an area of low concentration.
What factors affect the rate of diffusion?
- Concentration gradient
- Temperature
- Surface area of a membrane
What are the adaptations of the lungs?
- Large surface area
- Alveoli and capillary walls are very thin
- Have a rich blood supply
What are the adaptations of the small intestine?
- Large surface area
- Villi have a single layer of surface cell
What is the definition of osmosis?
- The movement of water from a solution with a high concentration of water to a solution with a low concentration of water, through a partially permeable membrane.
What does isotonic mean?
- When the concentration of water is the same inside the cell as outside
What does hypertonic mean?
When the concentration of water is higher inside the cell, than outside the cell.
What does hypotonic mean?
When the concentration of water is lower in the cell, than outside the cell.
Experiment: How do we find the effect of sugar solutions on plant tissue?
- Cut a potato into identical cylinders
- Get some beakers with different sugar solutions in them.(at least one should be pure water.)
- Measure the mass of the cylinders first
- Leave the potato cylinders in the solution for 24 hours.
- Take them out and dry them
- Measure their masses
- If the cylinders have drawn water, they would have a higher mass, and vice versa
What does dependent variable mean
he variable being tested or measured during a scientific experiment
What does independent variable mean?
the variable that is altered during a scientific experiment.
Where is active transport used in plants and humans
Plants = roots
Humans = gut
What is active transport
The process of substances being absorbed against a concentration gradient, using energy from respiration
What do culture mediums contain?
- Carbohydrates
- minerals
- proteins
- vitamins
What culture mediums can be used?
- nutrient broth solution
- agar jelly
How do you make an agar plate?
- Pour hot agar jelly into a petri dish
- When the jelly sets, transfer microrganisms to the culture medium by an inoculating loop.
What can be used instead of an inoculating loop?
- sterile dropping pipette or spreader.
How can we investigate the effect of antibiotics on bacterial growth?
(Practical)
1.Place paper discs soaked in different types of antibiotics on an agar plate, that has an even covering of bacteria.
2.The antibiotic will diffuse into the agar jelly
3.If there is bacteria immune to the antibiotic, it will continue to grow, else it wil die, forming an inhibition zone.
4.Use a control paper disc that hasn’t been soaked in antibiotic, but instead with sterile water.
5.Leave for 2 days at 25C
6.Record inhibition zone sizes.
How can we make sure the cultures don’t get contaminated?
- Heat petri dish and culture medium to a high temperature
- Pass inoculating loop through a hot flame
- Petri dish lid should be lightly taped on to stop microorganisms from the air getting in
- Petri dish should be stored upside down, so condensation doesn’t fall onto agar surface.
