Eukaryotic cells and organelles

Question 1

What are eukaryotic and prokaryotic cells?

Answer 1

Eu: make up eu. organisms, complex, e.g. all animal, plant, algae and fungi cells.

Pro: are prokaryotic organisms (single-celled organisms), simple, e.g. bacteria

Question 2

What are the differences between pro. and eu. cells?

Answer 2

P:

no nucleus - loop of DNA

no proteins associated with DNA

no introns

Eu. :

DNA in nucleus, in linear chromosomes

Have proteins (histones)

However, mitochondria and chloroplasts have DNA that’s in a loop (circular) as well.

Question 3

Structure of Eukaryotic cells:

• Label plant and animal cell
• Describe Algal and Fungal cells

Answer 3

Algal and Fungal Cells
1) Algal cells are a lot like plant cells - they have all the same organelles, including a cell wall and chloroplasts. They can be single celled.

2) Fungal cells are also a lot like plant cells, but with two key differences:

their cell walls are made of chitin, not cellulose.
they don’t have chloroplasts (because they don’t photosynthesise).

Question 4

What are the extra organelles found in plant cells that aren’t found in animal cells?

Answer 4

• a cellulose cell wall with plasmodesmata (‘channels’ for exchanging substances with adjacent cells)
• a vacuole (compartment that contains cell sap),
• chloroplasts.

Question 5

What might you see in plant cells that aren’t organelles?

Answer 5

You might also see starch grains in plant cells, although they’re not organelles. Plants use starch grains to store excess sugars.

Question 6

Give some examples of fungi

Answer 6

e.g. mushrooms and yeast

Question 7

What is the structure and function of:

the cell surface (plasma) membrane?

Answer 7

Question 8

What is the structure and function of:

the nucleus

Answer 8

Question 9

What is the structure and function of:

a mitochondrion

Answer 9

Question 10

What is the structure and function of:

a chloroplast

Answer 10

Question 11

What is the structure and function of:

the golgi apparatus

Answer 11

Question 12

What is the structure and function of:

a golgi vesicle

Answer 12

Question 13

What is the structure and function of:

a lysosome?

Answer 13

Question 14

What is the structure and function of:

a ribosome?

Answer 14

Question 15

What is the structure and function of:

the rough endoplasmic reticulum?

Answer 15

Question 16

What is the structure and function of:

smooth endoplasmic reticulum?

Answer 16

Question 17

What is the structure and function of:

the cell wall?

Answer 17

Question 18

Where are specialised cells found?

Answer 18

In multicellular organisms

Question 19

Answer 19

1. cell wall
2. capsule
3. plasmids
4. circular DNA
5. flagellum
6. cytoplasm

Question 20

In a virus what is the function of:

Answer 20

The cell wall supports the cell and prevents it from changing shape. It’s made of a polymer called murein.
Murein is a glycoprotein (a protein with a carbohydrate attached).

Question 21

In a virus what is the function of the capsule?

Answer 21

Some prokaryotes, e.g. bacteria, also have a capsule made up of secreted slime. It helps to protect bacteria from attack by cells of the immune system.

Question 22

In a virus what is the function of: a plasmid

Answer 22

Plasmids are small loops of DNA that aren’t part of the main circular DNA molecule. Plasmids contain genes for things like antibiotic resistance, and can be passed between prokaryotes. Plasmids are not always present in prokaryotic cells. Some. prokaryotic cells have several.

Question 23

In a virus what is the function of: the circular DNA

Answer 23

Unlike a eukaryotic cell, a prokaryotic cell doesn’t have a nucleus. Instead, the DNA floats free in the cytoplasm. It’s circular DNA, present as one long coiled-up strand. It’s not attached to any histone proteins

Question 24

In a virus what is the function of: the flagellum

Answer 24

The flagellum (plural flagella) is a long, hair-like structure that rotates to make the prokaryotic cell move. Not all prokaryotes have a flagellum. Some have more than one.

Question 25

In a virus what is the function of: the cytoplasm

Answer 25

The cytoplasm of a prokaryotic cell has no membrane-bound organelles (unlike a eukaryotic cell). It has ribosomes but they’re smaller than those in a eukaryotic cell.

Question 26

In a virus what is the function of: the plasma membrane

Answer 26

It’s mainly made of lipids and proteins. It controls the
movement of substances into and out of the cell.

Question 27

Describe viruses.

Answer 27

Viruses are Acellular

• They’re even smaller than bacteria-e.g. HIV is about 0.1 μm across.
• Unlike bacteria, viruses have no plasma membrane, no cytoplasm and no ribosomes.
• All viruses invade and reproduce inside the cells of other organisms. These cells are known as host cells.