Cell Biology Lecture 1

Question 1

How many cell types are in the human body?

Answer 1

About 200

Question 2

How large is a bacterium (prokaryote)?

Answer 2

0.1-1 micrometres in size (0.1-1x10^-9m)

Question 3

Do prokaryotes have any internal compartmentalization?

Answer 3

No

Question 4

Where is the genome (DNA) of the bacterium (prokaryote) kept?

Answer 4

The genome (DNA) lies freely in the cell as a ring of DNA

Question 5

Is there a nucleus present in a prokaryote?

Answer 5

No

Question 6

Do prokaryotes have a cell wall?

Answer 6

Yes

Question 7

Do prokaryotes have a plasma membrane?

Answer 7

Yes

Question 8

An example of a prokaryote which is photosynthetic (phototropic)?

Answer 8

Cyanobacteria

Question 9

Do prokaryotes have cytoskeleton?

Answer 9

Nah g

Question 10

Function of nucleus

Answer 10

Contains genome, site of DNA and RNA synthesis, surrounded by nuclear envelope

Question 11

Function of nucleolus

Answer 11

rRNA genes, RRNA, ribosomal proteins, ribosome subunit assembly

Question 12

Function of cytoplasm

Answer 12

Contains organelles and cytosol

Question 13

Function of cytosol

Answer 13

Place for many essential chemical reactions and protein synthesis

Question 14

Function of endoplasmic reticulum (ER)

Answer 14

Membrane enclose labyrinthine space. Rough ER contains ribosomes for protein synthesis. ER also produced lipids and functions as a calcium ion store

Question 15

Function of Golgi apparatus

Answer 15

Stacks of flattened membrane, receives lipids and proteins from the ER, modifies them and dispatches them to other parts or the exterior of the cell

Question 16

Function of mitochondria

Answer 16

Consume oxygen to oxidise food molecules (e.g sugar) and produce cellular energy (ATP). Released carbon dioxide

Question 17

Function of chloroplasts (In plants and algae only)

Answer 17

Consumes carbon dioxide and uses sunlight to produce sugar and oxygen

Question 18

Function of lysosomes

Answer 18

Contains digestive enzymes to degrade defunct organelles, macromolecules, as well as particles taken up from the outside of the cell via endocytosis. Releases nutrients from break down of food particles

Question 19

Function of endosomes

Answer 19

Endocytosed material must pass through the endosomes before being delivered to lysosomes

Question 20

Function of peroxisomes

Answer 20

Contains enzymes for various oxidative reactions involving hydrogen peroxide to inactivate toxic molecules

Question 21

What is the exchange between different organelles and the outside of the cell mediated by?

Answer 21

Vesicles

Question 22

Bulk import of macromolecules into the cell is

Answer 22

Endocytosis

Question 23

Bulk export of broken down molecules out of the cell is

Answer 23

Exocytosis

Question 24

Do prokaryotes have cytoplasmic organelles?

Answer 24

No

Question 25

What is the size of a eukaryotic cell?

Answer 25

10-100 micrometres

Question 26

What is the endosymbiotic theory?

Answer 26

Evolution of eukaryotic cells.
An anaerobic pre-eukaryotic cell (archaebacterium) through endocytosis, engulfs a prokaryotic mitochondria (primitive form). Instead of digesting it, these two cells lived symbiotically. Evolution allowed the cell to become aerobic and synthesis ATP.
Prokaryotic photosynthetic bacterium ingested via endocytosis by early eukaryotic cell, evolved into photosynthetic plant cells.