B1-Cell Biology

How is the DNA of Prokaryotic cells different from that of Eukaryotic cells?

Prokaryotic cells' DNA are not enclosed in a nucleus

Compare the size of prokaryotic and eukaryotic cells.

Prokaryotic cells are smaller than eukaryotic cells

What is differentiation?

The process by which a cell becomes specialised for its function

What are sperm cells specialised for?

for fertilisation

How is a sperm cell specialised for its function?

long tail and mitochondria for swimming, streamlined head for effective swimming, and enzymes to penetrate the egg membrane

What are nerve cells specialised for?

sending electrical impulses around the body

How is a nerve cell specialised for its function?

long axon to carry electrical impulses around the body, myelin to insulate axon, signalling up transmission synapses - junctions to pass impulses from one neuron to another, dendrite to increase surface area for better connections

What are muscle cells specialised for?

to contract (get shorter)

How is a muscle cell specialised for its function?

contain protein fibres packed with mitochondria for energy for contraction work together to form muscle tissue

What is a root hair cell specialised for?

Long, thin shape with tiny hairs to increase surface area for better absorption of water and minerals; does not contain chloroplasts.

What are xylem cells specialised for?

to transport water and minerals from roots to leaves(UPWARDS)

How is a xylem cell specialised for its function?

hollow tubes with thick walls containing lignin for strength and support

What are Phloem cells specialised for?

to transport sugars(food) from leaves to other parts of the plant

How is a phloem cell specialised for its function?

tubes with sieve plates and companion cells to move sugars effectively

What is Mitosis?

a type of cell division that produces 2 identical cells called daughter cells

Why do cells undergo mitosis?

for growth and repair

What happend duing mistsis

Cells grow and double in the number of subcellular structures, such as mitochondria and ribosomes. Chromosomes line up in the middle of the cell and are pulled to each end by protein fibres, cytoplasm and cell membrane split, forming 2 identical cells called daughter cells with the same number of chromosomes as the parent

What is microscopy?

The study of microorganisms using a microscope

How do light microscopes work?

They use light and lenses to form an image of a specimen and magnify it

How do electron microscopes work?

They use electrons instead of light to form an image

What is the first step of preparing a slide?

Add a drop of water to the middle of a clean slide.

What is the Second step for preparing a slide?

Cut up an onion and separate it into layers. Use the tweezers to peel off the epidermal tissue from the bottom of one of the layers

What is the third step for preparing a slide?

Using the tweezers, place the epidermal tissue onto the water on the slide

What's the fourth step for preparing a slide?

Add a drop of iodine solution onto the epidermal tissue. The iodine solution is a stain used to highlight features in a cell by adding colour to them

What is the fifth step for preparing a slide?

Place a coverslip on the epidermal tissue.Try not to get any air bubbles as it may obstruct your view

Explain how you prepare a specimen to be viewed under a microscope

1.) Add a drop of water in the middle of a clean slide

2.) Cut up an onion and separate it into layers. Use tweezers to peel some epidermal tissue from the bottom of one of the layers

3.) Using tweezers, place the epidermal tissue into the water in the slide

4.) Add a drop of iodine solution to the onion on the slide

5.) Place a Cover Slip over the specimen

What's the first step of using the microscope to observe the specimen?

clip the slide onto the stage using stage clips

What's the second step of using the microscope to observe the specimen?

select the lowest-powered objective lesn

What's the third step of using the microscope to observe the specimen?

Use the coarse adjustment knob to move the stage

What's the fourth step of using the microscope to observe the specimen?

Look down the eyepiece lens and use the coarse adjustment knob to move the stage downwards until the image is roughly in focus

What's the fifth step of using the microscope to observe the specimen?

Adjust the focus with the fine adjustment knob until you get a clear image of what's on the slide

What's the sixth step of using the microscope to observe the specimen?

If you need to see the slide with a greater magnification, swap to a higher-powered objective lens and refocus

What is the equation for magnification?

Image Size / Actual Size

How do we convert from millimetres to micrometres?

× 1000

How do we convert from micrometres to nanometres

× 1000

How do we convert from cm to mm

× 10

How do we convert from metres to cm?

× 100

How do we convert from m to mm?

×1000

How do we convert from m to µm?

×1,000,000