B1 - cell structure (PAPER 1)

What does an animal cell contain (hint: 4 parts)

Nucleus

Ribosomes

Mitochondria

Cell membrane

Name the parts of a plant cell (hint: 8 parts)

Ribosomes

Nucleus

Mitochondria

Chloroplast

Cytoplasm

Cell wall

Cell membrane

Vacuole

What does a nucleus do?

Controls all activity of the cell and contains genetic material

What does the cell membrane do?

Allows substances to move in and out of the cell

What does the cytoplasm do?

Where chemical reactions take place

What happens in the mitochondria

Energy is released by respiration

What is ribosomes?

Protein synthesis

What si the chloroplast?

Contains green pigment chlorophyll. Absorbs light for photosynthesis

What is the cell wall?

Strengthens cell and supports the plant

What is the vacuole?

Filled with cell sap. Keeps cell turgid

What are bacterial cells?

Bacterial cells do not have a true nucleus, they just have a single strand of DNA that floats in the cytoplasm.

Name the parts of a bacterial cell (hint: 5 parts)

Chromosome

Cell wall

Flagella

Cytoplasm

Cell membrane

Is a bacterial cell prokaryotic or eukaryotic?

Prokaryotic

How is big is eukaryotic cell?

5ym - 100ym

What si the outer layer of a eukaryotic cell?

Cell membrane (cell wall in plants and fungi)

What is the genetic material in the eukaryotic cell?

DNA in nucleus. Plasmids in some simple eukaryotic organisms.

What is the cell division for eukaryotic cells?

Mitosis

What is the size of prokaryotic cell?

0.2ym - 2ym

What is the outer layer of a prokaryotic cell?

Cell membrane surrounded by cell wall

What is genetic material for a prokaryotic cell?

DNA single molecule found free in cytoplasm (additional DNA in rings - plasminds)

What is the cell division for prokaryotic cells?

Binary fission

What are the three specialised cells in animals?

Sperm cell

Nerve cell

Muscle cell

What is the role of the sperm cell?

To get the male DNA to the female DNA

What are the adaptations of the sperm cell?

Long tail, lots of mitochondria to provide energy

What is the role of the nerve cell?

To send electrical impulses around the body

What are the adaptations of a nerve cell?

Long to cover more distance. Has branched connections to connect in a network.

What is the role of muscle cell?

To contact quickly

What are the adaptations of a muscle cell?

Long and contains lots of mitochondria for energy

What are the 3 specialised cells in plants?

Root hair cells

Phloem

Xylem

What is the role of the root hair cell?

To absorb with from the soil.

What are the adaptations of a root hair cell?

A large surface area to absorbs more water.

What the role phloem?

Transports substances around the plant.

What are the adaptations of the phloem?

Pores to allow cell sap to flow. Cells are long and joined end to end.

What is the role of the xylem?

Transports water through the plant.

What adaptions of the xylem?

Hollow in the centre. Tubes are joined.

How do you work magnification of the microscope?

Magnification of the magnification = magnification of eyepiece x magnification of objective

How do you find out the magnification of an image?

Magnification of an image = image size / actual size

What is the method to using microscope (hint: 7 steps)?

1. Put a drop a water on the microscope slide

2. Take a thin layer of onion skin (tweezers)

3. Place on a slide , make sure it’s flat with no air bubbles

4. Stain with 2 drops of iodine

5. Place a cover slip to secure. Rotate the objective lens so that it’s low power, e.g x10

6. Turn the coarse focus so that the stage is as close to the objective lens as possible. Use the fine focus lens

7. Draw a low power image or record a digital image of what you see. Then, rotate the objectives to a higher power object to see more detail.

In the human cell how many pairs of chromosomes are there in the nucleus?

23 pairs of chromosomes

What do chromosomes contain?

Chromosomes contain a double helix of DNA

What is a gene?

A gene is a short section of DNA that codes for a protein and as a result controls a characteristic.

What is the purpose of mitosis?

Growth and repair

What is the end point of mitosis?

One cell divides to form two genetically identical daughter cells.

What is the cell cycle?

1. Cell divides

2. DNA synthesis (chromosomes double)

3. Further growth and DNA checked

4. Mitosis

5. Cytoplasm and membrane separates

6. Rest

What is the process of mitosis?

1. cell begins to divide

2. DNA replicates

3. Nuclear membrane breaks down

4. Chromosomes line in the center

5. One set of each chromosome is pulled to the pole of the cell

6. Nucleus divides

7. Cytoplasm and membrane divide

8. Two genetically identical daughter cells produced

What is the definition of stem cells?

Undifferentiated cell which can specialise to form many more similar cells, of which some will differentiate to have different functions

What is embryonic stem cells?

Form when egg and cell fuse. Differentiate to form any cell. Potentially used to treat type 1 diabetes (pancreatic cells), neural cells (Alzheimer’s), or paralysis.

What is an adult stem cell?

Bone marrow - form many types of cell (not all)

What is a meristem (plant)?

Roots and shoot tips. Differentiate into any cell. Used for desirable traits such as disease resistance, research or to save a rare plant from extinction

What are the risks of stem cells?

Transfer viral infection, ethical / religious obligations, no guarantee, difficulty finding donors, mutations. Embryonic - aborted/spare IVF embryos destroyed (these embryos could have developed into a human).

What is therapeutic cloning?

An embryo produced has the same genes as the patient

What can you then do with the embryo produced?

The embryo produced can then be harvested to obtain the embryonic stem cells. These could be grown into an cells the patient needed.

What so the advantage of therapeutic cloning?

The advantage is that they would not be rejected as they would have the exact same genetic make-up as the individual.