T3L1 Ultrastructure of eukaryotic cells

Question 1

Name the 9 main structures in a Eukaryotic cell

Answer 1

Nucleus
Nucleolus
Rough ER
Smooth ER
Golgi apparatus
Lysosomes
Centrioles
Mitochondria
Cell surface membrane
(Cytoplasm)

Question 2

Describe the structure/function of the nucleus including the nucleolus

Answer 2

The nucleus is enclosed by an envelope of two membranes and contains genetic information in chromosomes.

Also within the nucleus is the nucleolus which is a dense body where ribosomes are made

Question 3

Describe the rER

Answer 3

the rER is found close outside the nucleus and is a system of interconnected membrane bound sacs studded with ribosomes.

Proteins are made in these ribosomes (protein synthesis - translation) and some modficiation occurs in the rER

Question 4

Describe the Golgi Apparatus

Answer 4

The Golgi is made of stacks od flattened membrane bound sacs , formed by fusion of vesicles from the ER.

Proteins come from rER to Golgi to be further modified (e.g add carbohydrate chains) and are then packaged into vesicles for transport

Question 5

Describe the sER

Answer 5

Similar to the rER (interconnected membrane bound sacs) but without ribosomes (hence smooth)

Makes lipids and steroids

Question 6

Describe the mitochondria

Answer 6

Has two membranes - inner is folded in on itself to form finger like projections - cristae

Site of respiration

Question 7

Describe the lysosomes

Answer 7

Spherical sacs

Contain digestive enzymes that are involved in the breakdown of unwanted cell structures

Question 8

Describe the centrioles

Answer 8

One pair of two hollow cylinders made up of microtubules (polymers of globular proteins arranged in a helix to form a hollow tube)

Involved in the formation of spindle fibres during nuclear division and transport within the cytoplasm

Question 9

Describe the cell surface membrane

Answer 9

Phospholipid bilayer membrane containing proteins and other molecules