Cell Organelles

Question 0

Nucleus function

Answer 0

Houses nearly all the cells genetic material. The chromatin consists of DNA and proteins. Has the instructions for making proteins. Some of these proteins regulate the cells activities. When cells divide chromatic condenses into visible chromosomes. The nucleus makes RNA and ribosomes, these pass into the cytoplasm and proteins are assembled there.

Question 1

Structure of the nucleus

Answer 1

Largest organelles
When stained shows darkened patches called CHROMATIN
Surrounded by a double membrane called a nuclear envelope, which has a lot of holes ( nuclear pores) large enough to allow relatively large molecules through. There is a dense spherical structure called the NUCLEOLUS, inside the nucleus.

Question 2

Endoplasmic reticulum structure?

Answer 2

Consists of a series of flattened, membrane bound sacs called cisternae. They are continuous with the outer nucleus membrane. Rough er have ribosomes.

Question 3

ER function?

Answer 3

Rough Er transports the proteins made on the ribosomes. Some will be secreted from the cell and others will be placed on the cell surface membrane. Smooth er is involved in making lipids which the cell needs

Question 4

Golgi apparatus structure

Answer 4

A stack of membrane-bound flattened sacs

Question 5

Golgi apparatus function

Answer 5

Receives proteins from the ER and modifies them. May add sugar to them.it then packages the modified proteins into vesicles that can be transported. Some proteins may go to the surface of huge cell to be secreted

Question 6

Mitochondria structure

Answer 6

Spherical or sausage-shaped. Two membranes separate by a fluid filled space. The inner membrane is tightly folded and called the crustae. Central part (galps between the inner membrane< cristae> is called th matrix.

Question 7

Mitochondria function

Answer 7

Produces most of the ATP ( adenosine triphosphate) during respiration, ATP is often called the universal energy carrier because almost all activities in the cell are driven by the energy released from ATP

Question 8

Chloroplasts structure

Answer 8

PLANT CELLS AND THE CELLS OF SOME PROTOCTISTS.
have two membranes separated by fluid. Inner membrane is continuous, flattened membrane sacs called THYLAKOIDS. These look like piles of plates and a stack of them are called a granum. Chlorophyll molecules are on the thylakoids and in the intergranal membranes.

Question 9

Lysosomes structure

Answer 9

Spherical sacs surrounded by a single membrane

Question 10

Lysosomes functions

Answer 10

Contain powerful digestive enzymes.
Role is to break down materials
Eg, specialized lysosomes on head of sperm help to penetrate the egg by breaking down the material surrounding the egg

Question 11

Ribosomes structure

Answer 11

Tiny organelles.
Some free in the cytoplasm others bound to ER (rough)
Each ribosome = two subunits

Question 12

Ribosomes functions

Answer 12

Ribosomes are the site of protein synthesis.

Act as an assembly line where mRNA from the nucleus is used to assemble proteins from amino acid.

Question 13

Centrioles structure

Answer 13

These are small tubes of protein fibers (microtubules). There is a pair of them next to the nucleus in animal cells and in the cells of some protoctsits.