Chapter 1- Cell

Question 1

CELL SURFACE MEMBRANE

Answer 1

Partially permeable barrier which controls the exchange of materials such as nutrients and waste product between cell and environment.

7nm ( 3 layers called trilaminar appearance )

Question 2

NUCLEAR ENVELOPE

Answer 2

Outer membrane is continuous with ER and maybe ribosomes

Question 3

NUCLEAR PORES

Answer 3

Allows exchange of substances between nucleus and cytoplasm.
Eg: the mRNA and newly made ribosomes can leave and molecules needed for manufacture of ribosomes and DNA and the regulation of DNA can enter.

Question 4

CHROMATIN

Answer 4

Coil of DNA bound to proteins called histones .

Controls the cell activities because it contains genetic information in the form of DNA

Question 5

NUCLEOLUS

Answer 5

Makes ribosomes

Question 6

R- ER

Series of flattened sacs

Answer 6

Concerned with transport of protein made by ribosomes.( A receptor in the membrane of ER provides a channel through which the RER folds and processes proteins made on the ribosomes.

Question 7

S- ER

Membrane bound sacs

Answer 7

Lipid synthesis. Also makes steroids which are type of lipid.

Question 8

Ribosomes

Answer 8

Protein synthesis.
Two types
70S -> prokaryotes
80S -> Eurakyotes

Question 9

Mitochondrion

Oval shaped,bound by a double membrane called the envelope

Answer 9

▪️Major sites of aerobic respiration within cells.
▪️Lipid synthesis .
▪️the inner membrane is folded to form projections called cristae with matrix on the inside containing all the enzymes needed for respiration

Question 10

Golgi apparatus

Series of fluid filled ,flattened and curved sacs

Answer 10

▪️Golgi body collects, processes and sorts molecules( particularly proteins from RER) ready for transport in golgi vesicles either to other parts of the cell or out of the cell.(secretion)
▪️golgi vesicles used to make lysosomes

Question 11

Lysosomes

Answer 11

▪️Lysosomes are responsible for breakdown(digestion) of unwanted structures such as old organelles or even whole cells as in mammary glands after lactation(Brest feeding)

▪️in WBC lysosomes are used to digest bacteria .

Question 12

Centrioles

Answer 12

▪️hollow cylinders containing a ring of micro tubules arranged at right angles to each other
▪️involves in cell division
▪️

Question 13

Vacuole

Answer 13

▪️Fluid filled sad present in plant cells surrounded by a membrane called tonoplast.

▪️ it contains mineral salts ,sugars,amino acids,waste substances and pigments

▪️Role is to color the cell to attract pollinating insects ,act as temporary food store and provide support through turgidity

Question 14

Cell wall

Answer 14

Made of cellulose microfibrils

Role is to strengthen the cell and prevent bursting due to osmosis

Question 15

Capsule

Answer 15

Protective slimy layer which helps the cell to retain moisture and adhere to surfaces

Question 16

Diffentiate

Answer 16

Prokaryotes.            Eukaryotes
▪️Diameter=0.5-5.      ▪️40um
▪️DNA circular.       ▪️DNA nucleus 
And in cytoplasm.       
▪️70S.                      ▪️80S
▪️cell wall present.   ▪️sometimes present