Animal cells

Question 1

Describe the structure of the Nucleus

Answer 1

Largest cell organelle, enclosed by an envelope of two membranes that is perforated by nuclear pores. It contains chromatin which is the extended, useable form of chromosomes.
Also contains a darker area called the nucleolus.

Question 2

Describe the function of the Nucleus

Answer 2

Chromatin/chromosomes are made of DNA which is the molecule of inheritance.
DNA is organised into genes which each code for a protein.

The nucleolus makes ribosomes.

Question 3

Describe the structure of the Cell membrane

Answer 3

Phospholipid bilayer.

Made of phospholipids in two layers with proteins present. This structure described by the Fluid Mosaic Model.

Question 4

Describe the function of the Cell membrane

Answer 4

A partially permeable barrier controlling exchange between the cell and its environment.

Also found around cell organelles e.g. nucleus, lysosomes etc.

Question 5

Describe the structure of the Mitochondria

Answer 5

Two membranes forming an envelope, where the inner membrane is highly folded to form christae. Inner space is called the matrix.

Question 6

Describe the function of the Mitochondria

Answer 6

Site of aerobic respiration in cells. Note – anaerobic respiration occurs in the cytoplasm.

Question 7

Describe the structure of the Endoplasmic reticulum

Answer 7

A system of flattened membrane bound sacs called cisternae forming tubes and sheets. Joined to outer membrane and nucleus.

Question 8

Describe the function of the Endoplasmic reticulum

Answer 8

If ribosomes are found on its surface it is called rough ER, and transports proteins made by the ribosomes. Smooth ER (no ribosomes) is the site of lipid synthesis.

Question 9

Describe the structure of the Ribosome

Answer 9

Very small organelles consisting of a large and small subunit. Made of protein and RNA.

Question 10

Describe the function of the Ribosome

Answer 10

Can be attached to endoplasmic reticulum (RER) or free in the cytoplasm.

Site of protein synthesis.

Question 11

Describe the structure of the Golgi apparatus

Answer 11

A stack of flattened membrane bound sacs, called cisternae, continuously being formed at one end of the stack (cis) and budded off as vesicles at the other end (trans).

Question 12

Describe the function of the Golgi apparatus

Answer 12

Internal processing and transport system e.g. of proteins formed by ER.

Make lysosomes.

Question 13

Describe the structure of the Microvilli

Answer 13

Cellular membrane protrusions containing microfilaments that form a brush border on the cell’s outer surface. Increase the surface area of cells. Not present on all cell types.

Question 14

Describe the function of the Microvilli

Answer 14

Involved in a wide variety of functions, including absorption, secretion, cellular adhesion.

Question 15

Describe the structure of the Lysosome

Answer 15

A simple spherical sac bounded by a single membrane. Contain hydrolytic enzymes.

Question 16

Describe the function of the Lysosome

Answer 16

Many functions all concerned with the breakdown of structures or molecules. E.g. getting rid of old organelles, digesting bacteria, cell suicide.

Question 17

Describe the structure of the nucleolus

Answer 17

Dense spherical structure in the middle of the nucleus.

Question 18

Describe the function of the nucleolus

Answer 18

The nucleolus makes RNA and ribosomes.

Question 19

Describe the structure of the vesicles

Answer 19

Small spherical membrane bound sacs with fluid inside.

Question 20

Describe the function of the vesicles

Answer 20

Transport vesicles are used to transport materials inside
the cell and secretory vesicles transport proteins that
are to be released from the cell, to the cell surface membrane.

Question 21

Describe the structure of the centrioles

Answer 21

They are small tubes of protein fibres.

Question 22

Describe the function of the centrioles

Answer 22

They form spindle fibres during cell division.