Lab Exercise nos. 3, 4, and 5

Question 1

Cell

Answer 1

• fundamental structural and functional unit of life (no exceptions – these are for all living organisms)
• possess the hereditary material

Question 2

Organisms life depends upon ____

Answer 2

Organisms life (for both unicellular and multicellular) depends upon the integrity of cell structures and its stability is kept by energy transformation

Question 3

Types of Cell

Answer 3

Prokaryote/Prokaryotic cell

Eukaryote/Eukaryotic cell

Question 4

Prokaryotic Cell

Answer 4

• simpler and smaller (1-10µm in diameter)
• absence of nucleus and most membranous organelles
• flagella (for mobility) and pili (for communication between cells) is found on its surface
• cell wall (additional covering other than plasma membrane; contributes to cell’s rigidity); capsule (another additional covering in some bacteria)
• cytoplasm contains DNA, ribosomes and various inclusions

Question 5

Prokaryotic Cell example

Answer 5

Bacteria and Archaea

Question 6

Eukaryotic Cell

Answer 6

-complex and larger than prokaryotic cell (10-100µm in diameter)
-presence of nucleus and membranous organelles such as endoplasmic reticulum, golgi complex, lysosome, mitochondria, microbodies, vacuoles, and chloroplasts (for plants only), cytoskeleton (for mechanical support)
-cell wall (additional covering for plants only);
plasma membrane (cell’s covering)
-cytoplasm contains organelles

Question 7

Example of Eukaryotic Cells

Answer 7

Animals, Plants, Fungi, and Algae

Question 8

What does “integrity” of the cell structure suggest?

Answer 8

It suggests it is working well/it does its function well.

Question 9

What do cell activities require?

Answer 9

First and foremost, different cell activities requires energy and energy can be converted to different forms.

Question 10

What does “pro” in prokaryote mean?

Answer 10

Means “before”

Question 11

What does “eu” in eukaryote mean?

Answer 11

Means “true”

Question 12

What is the root word of both prokaryote and eukaryote?

Answer 12

Karyon – which means nucleus

Question 13

What is the size of prokaryotic cells compared to eukaryotic cells?

Answer 13

It is about 1/10 the size of eukaryotic cells.

Question 14

What happens to hereditary material if there is no nucleus?

Answer 14

• the DNA is naked because of the absence of the nucleus

Question 15

What does membranous organelles mean?

Answer 15

Keep in mind that not only the cell has covering, but organelles themselves have what is called the “organelle membrane” or “membrane bounded”

note: the latter term is found in the lab manual

Question 16

What is the purpose of the cell wall in prokaryotic cells?

Answer 16

To contribute to rigidity.

Question 17

What is the shape of the flagella?

Answer 17

It appears to be whipped-like in appearance

Question 18

What is the position of cell wall and cell membrane respectively?

Answer 18

Outer and inner

Question 19

What will the cell wall and cell membrane do?

Answer 19

These coverings will protect the cell from the outside environment – both of them.

Question 20

Nucleoid

Answer 20

Just a space where you can find the DNA

Question 21

True or false. The nucleus is not an organelle.

Answer 21

FALSE. The nucleus is an organelle (especially when referred to the lab manual).

Question 22

What is the reason why the cell has distinct shapes?

Answer 22

Because of the presence of the cytoskeleton.

Question 23

Boundaries of cytoplasm

Answer 23

Bet. the outside of the nucleus and the plasma membrane.

Question 24

What does a cell mainly consist of?

Answer 24

The cell mainly consists of a fluid filled space called cytoplasm.

Question 25

What is the cell surrounded by?

Answer 25

It is surrounded by a cell membrane.

Question 26

What does the cytoplasm contain?

Answer 26

The cytoplasm contains a nucleus, mitochondria, Golgi bodies, endoplasmic reticulum, lysosomes, ribosomes, and vacuoles.

Question 27

What additional boundary wall do plants have?

Answer 27

Plants have an additional boundary wall called the cell wall, which is absent in animal cells.

Question 28

What do plant cells have that occupies most of the volume in the plant cell?

Answer 28

Plant cells have large filled vacuoles which occupy most of the volume in the mature plant cell.

Question 29

What other organelle do plant cells contain which is absent in animals?

Answer 29

Chloroplast

Question 30

What are the materials required to prepare a stained temporary mount of an onion peel?

Answer 30

1. Cover slip
2. Glycerine
3. Glass slides
4. Onion
5. Watch glass
6. Distilled water
7. Safranin solution
8. Forceps
9. Brush
10. Needle
11. Compound microscope
12. Blotting paper
13. Dropper

Question 31

PROCEDURE TO PREPARE A STAINED TEMPORARY MOUNT OF AN ONION PEEL

Answer 31

1. Pour some distilled water from a bottle into a watch glass.
2. Take half a piece of an onion and remove leaves from the onion piece.
3. Remove a piece of transparent onion peel with the forceps.
4. Put the epidermis into a watch glass containing distilled water.
5. Take some Safranin solution using a dropper.
6. Put a few drops of Safranin into another watch glass.
7. Using a brush, transfer the peel into the watch glass with Safranin solution.
8. Keep the epidermis for 30 secs in Safranin solution so the peel can become stained.
9. Take the peel from Safranin solution using the brush and put it in the watch glass containing distilled water.
10. Using a dropper, put some glycerine and put 2-3 drops of glycerine in the middle of a dry glass slide.
11. Transfer the peel to the slide containing glycerine using the brush.
12. Take a cover slip and place it gently on the peel with the help of a needle.
13. Remove the extra glycerine using the blotting paper.
14. Take the glass slide and put it under the microscope.
15. View the slide under the compound microscope.

Question 32

OBSERVATIONS OF ONION CELL

Answer 32

A large number of regularly shaped cells are lying side by side. Each cell has a distinct cell wall. A distinct nucleus is present on the periphery of each cell. Lightly stained cytoplasm is observed in each cell. A large vacuole is present in the centre of each cell, surrounded by the cytoplasm.