cells and microscopes

Question 1

Nucleus

Answer 1

• controls the cell

- contains genetic material (chromosomes which contain DNA)

Question 2

Cytoplasm

Answer 2

• a jelly-like substance where most of the cell’s activities take place

Question 3

Cell Membrane

Answer 3

• like a very thin bag.
• It controls what enters and exits the cell and separates one cell from another.
• It is a semi-permeable membrane which means it only lets some things in and some things out.

Question 4

Mitochondria

Answer 4

• jelly-bean shaped structures in which aerobic respiration occurs
• (very difficult to see with a light microscope)
• makes energy for the cell by converting chemical energy in food into energy in a form that is usable to the cell

Question 5

Ribosomes

Answer 5

• tiny round structures which make new proteins for the cell (protein factory).
• They are found in the cytoplasm (they cannot be seen with a light microscope because of their small size).

Question 6

Field of View

Answer 6

the circular area you see in a microscope

Question 7

Micrographs/ Electron micrographs

Answer 7

pictures taken from microscopes

Question 8

Why are scale bars used?

Answer 8

they are used on micrographs to estimate real sizes

by using the formula: magnification = image / actual

Question 9

Cell wall

Answer 9

• the cell wall is made of cellulose which is a long-chain polymer of glucose molecules joined together
• it supports and protects the cell
• it makes the cell rigid and maintains the shape of the cell

Question 10

Vacuole

Answer 10

• plants have a large vacuole which stores cell sap and other substances that can be used at a later time
• helps to keep the cell firm and rigid

Question 11

Chloroplasts

Answer 11

• organelles that contain chlorophyll which traps sunlight which is used in photosynthesis along with carbon dioxide and water
  carbon dioxide + water + (sunlight) ==> glucose + oxygen
• chlorophyll is a green pigment

Question 12

Practical- Using Microscopes

Answer 12

• Decide which cells to observe and how you will collect them.
• Collect a small specimen of the cells
• Add a drop of water or stain to the centre of a microscope side. Record the name of the stain you have used.
• Place your specimen on the drop of water or stain.
• Use a toothpick to slowly lower a coverslip onto the specimen. The cover slip keeps the specimen flat, holds it in place and stops it drying out.
• Examine your specimen under a microscope. Start with the lowest magnification and work up to higher magnifications. Illustrate one or more of the cells you see and annotate your drawing appropriately.

Question 13

Eukaryotic cells

Answer 13

cells with a nucleus