3.1 - Eukaryotic Cell Structure (Animals and Plants)

Question 1

Lysosomes (2S and 2F):

Answer 1

Structure:

1. Contain hydrolytic enzymes.
2. Surrounded by a membrane to keep enzymes separate from the cytoplasm of the cell.

Functions:

1. Digest pathogens- This process uses enzymes.
2. Break down waste material - This material includes old organelles and cells.

Question 2

Smooth endoplasmic reticulum (1S and 1F):

Answer 2

Structure:

• Same as the rough endoplasmic reticulum without the ribosomes.

Function:

• Synthesis, storage, and transport of lipids and carbohydrates- For example, cholesterol and steroid hormones.

Question 3

Rough endoplasmic reticulum (2S and 1F):

Answer 3

Structure:

• Contains a network of membranes enclosing a fluid-filled space, known as cisternae.
• The surface of the cisternae is covered with ribosomes.

Function:

• Synthesis and transport of proteins - The proteins are made using the ribosomes.

Question 4

Golgi apparatus (2S and 3F):

Answer 4

Structure:

1. Contain fluid-filled, membrane-bound sacs known as cisternae.
2. Contain smaller vesicles.

Functions:

1. Process and package lipids and proteins- Carried out by the cisternae.
2. Store and transport lipids and proteins- Carried out by the vesicles.
3. Synthesise lysosomes - Specialised vesicles.

Question 5

Ribosomes (3S and 1F):

Answer 5

Structure:

1. Made up of proteins and rRNA (ribosomal RNA).
2. Consist of a large and a small subunit.
3. Not surrounded by a membrane.

Function:

• Site of protein synthesis - Involved in the process of translation.

Question 6

Mitochondria structure and function (3S and 1F):

Answer 6

Structure:

1. Contain an enzyme-rich liquid known as the matrix.
2. Surrounded by a double membrane in which the inner membrane is folded to form structures known as cristae.
3. Contain their own DNA (mtDNA) and ribosomes.

Function:

• Site of aerobic respiration - Produces ATP.

Question 7

Cell surface membrane structure and functions (2 for each):

Answer 7

Structure;

1. found on the surface of animal cells
2. mainly made up of lipids and proteins

Functions;

1. controls the movement of substances into and out of the cells - membrane is partially permeable
2. cell signalling - receptors can detect signals from other cells

Question 8

Nucleus structure and functions (3 each):

Answer 8

structure;

1. contains genetic information in the form of chromosomes
2. contains a structure known as the nucleolus
3. surrounded by a nuclear envelope containing pores

functions;

1. controlling the cell’s activities - contains DNA with instructions to produce proteins
2. synthesis of ribosomes - nucleolus makes rRNA
3. exchange between nucleus and cytoplasm - substances can enter or leave the nucleus via the nuclear pores

Question 9

Difference between eukaryotic and prokaryotic cells:

Answer 9

• Eukaryotes are mostly multicellular organisms, and have more complex membrane bound organelles - have DNA in the form of chromosomes within a nucleus
• Prokaryotes are single-celled organisms made up of prokaryotic cells like bacteria