Eukaryotic Cells and Organelles.

Question 1

Describe the structures within the nucleus.

Answer 1

1. Chromatin
2. Nuclear Envelope
3. Nucleolus
4. Nuclear Pores

Question 2

Describe the function of the nucleolus.

Answer 2

Manufactures ribosomes.

Question 3

Describe the structure of chromatin.

Answer 3

Made from DNA and proteins.

Question 4

Describe the function of the nuclear pores.

Answer 4

Pores allow mRNA and other molecules to leave the nucleus and enter the cytoplasm of the cell.

Question 5

Describe the function of the nucleus.

Answer 5

Controls the cell’s activities and makes ribosomal RNA (rRNA)

Question 6

Describe the features of the nuclear envelope.

Answer 6

Surrounds the nucleus, creating a double membrane organelle, and contains pores.

Question 7

What is a lysosome?

Answer 7

A round organelle with no clear internal shape that contains hydrolytic enzymes.

Question 8

Describe the function of the lysosomes.

Answer 8

Digests invading cells, breaks down worn out/dead components of the cell and can release enzymes to the outside of the cell via exocytosis.

Question 9

Describe the structure of a ribosome.

Answer 9

A ribosome is made of proteins and RNA. It is split into two; a small subunit and a large subunit.

Question 10

Describe the function of a ribosome.

Answer 10

It is the site where proteins are made. They either float free in the cytoplasm or are attached to RER.

Question 11

What is rough endoplasmic reticulum (RER)?

Answer 11

A system of folded membranes, that create a double membrane, and are covered in ribosomes. They enclose cisternae, fluid filled sacs that allow material to be transported through the cell.

Question 12

Describe the function of RER.

Answer 12

It is the site of translation- folds and processes proteins that have been made at the ribosome.

Question 13

Describe the structure of smooth endoplasmic reticulum (SER)

Answer 13

A complex system of sheet like double membranes enclosing cisternae.

Question 14

Describe the function of SER.

Answer 14

It is the site of lipid, steroid and carbohydrate synthesis.

Question 15

Describe the structure of the Golgi apparatus.

Answer 15

It is a group of fluid-filled sacs. It has a trans face (proteins leave apparatus) and a cis face (proteins enter apparatus). Transport vesicles are often found at the edge of the sacs.

Question 16

Describe the function of the Golgi apparatus.

Answer 16

• Processes and packages new lipids & proteins
• Makes lysosomes
• Secretes carbohydrates
• Assembles glycoproteins

Question 17

Describe the structure of a mitochondrion.

Answer 17

• Rod-shaped
• Double membrane (inner and outer membrane)
• Gaps between folded inner membrane called cristae
• Matrix contains lipids, proteins, ribosomes, loops of DNA and enzymes involved in respiration
• Surface of cristae is covered in stalked particles where ATP is made.

Question 18

Describe the function of a mitochondrion.

Answer 18

• Site of aerobic respiration
• Converts ATP into ADP
• Number of mitochondria reflect metabolic activity of cell

Question 19

Describe the structure of centrioles.

Answer 19

• 2 short bundles of hollow cylinders
• Triplet microtubules make up hollow cylinder
• Found in animal cells

Question 20

Describe the function of centrioles.

Answer 20

Involved in the separation of chromosomes, by forming the spindle at the poles of the cell, during cell division

Question 21

Describe the route during protein transport.

Answer 21

1. Ribosomes on RER make proteins that are excreted/attached to cell membrane. Free ribosomes in cytoplasm make proteins that stay in cytoplasm
2. Proteins produced at RER are folded & processed in RER
3. They are then transported from ER to Golgi apparatus in transport vesicles
4. Proteins may undergo further processing at Golgi apparatus
5. Proteins enter more vesicles to be transported around the cell.