cell structure

Question 1

structure RER

Answer 1

-memb organelle
-flattened fluid filled sacs called cisternae.
-interconnected with 80s ribosomes attached to it
-more regular than SER
-continuous with outer nuclear envelope
-extended in almost the entire cytoplasm

Question 2

structure SER

Answer 2

-memb organelle
-tubular, fluid filled sac
-no ribosomes
-irregular

Question 3

function SER

Answer 3

-synthesis of lipids, cholesterol and steroids such as sex hormones
-transport steroids to Golgi app
-breaks down toxic substances in liver

Question 3

function RER

Answer 3

-post translational modification of proteins
-transport proteins to Golgi app

Question 4

Golgi structure

Answer 4

-memb organelle
-flattened fluid filled sacs called cisternae
-arranged in a stack, parallel to each others swollen at both ends, with Golgi vesicles surrounding them

Question 5

Golgi function

Answer 5

-processing, chemical modification and glycosylation of proteins
-packaging of protein into secretory vesicles and lysosomes

Question 6

structure ribosomes

Answer 6

-non memb organelle
-measures 20-25 nm
-made of two subunits a large and small subunit each is made of proteins and rRNA
-large subunit has 2 buildings sites for 2 tRNA
-the small subunit allows mRNA binds to it

Question 7

function ribosomes

Answer 7

polypeptide snythesis

Question 8

structure secretory vesicle

Answer 8

-spherical
-memb organelle
-measures 0.5 nm

Question 9

structure of cilium

Answer 9

-each cilium has 2 central microtubules & a ring of nine microtubule doublets on the side “9+2”

Question 9

the MTDs structure

Answer 9

the wall of the A-microtubule is a complete ring of 13 protofilaments and B-microtubule attached is an incomplete ring with 10 protofilaments.

each A-microtubule has inner & outer arms made of dynein

Question 10

function secretory vesicle

Answer 10

-they pinch off Golgi App, move to cell surface memb guided by microtubules “cytoskeleton” using ATP, fuse with it as both are fluid in nature, and release its contents out of cell by exocytosis

Question 10

lysosomes structure

Answer 10

-spherical
-memb organelle that has hydrolytic enzymes
-it measures 0.5µm

Question 10

lysosomes function

Answer 10

-stores inactive hydrolytic enzymes

-phagocytosis: moves towards the phagocytic vesicle, fuse with it, as the memb are fluid and release its hydrolytic enzymes as protease to digest cell memb

-autophagy: digest worn out or dead organelles such as mitochondria

-autolysis: digestion of the parent cell by lysosomes

-secretion of enzymes: enzymes in the acrosomes of sperms

Question 10

beating mech

Answer 10

the inner and outer dynein arms connect with B-microtubules of neighboring MTDs
-MTDs slide past each other using ATP- the sliding motion is converted into bending- beating movement

Question 11

structure cellulose cell wall

Answer 11

2ry cell wall: founded in most cells not all
importance: rigid layer that supports plant cells

1ry cell wall: between middle lamella and secondary cell wall
importance: provides strength to the cell wall, but its also flexible to allow cell growth

middle lamella: outer layer of cell wall that mainly contains pectin
importance: cell to cell adhesion

Question 11

prokaryotic flagellum

Answer 11

prokaryotic flagellum is a protein divided into 3 parts: filament, hook & basal body

Question 12

structure cell sap vacuole

Answer 12

-memb organelle
-surrounded by tonoplast
-filled with sap

Question 13

function cell vacuole

Answer 13

function:
-support:
concentrated vacuole- low water potential gradient so water enters vacuole by osmosis, increasing pressure in cell keeping plant turgid, so support the stem.

-lysosomal activity:
anthocyanin pigments
alkaloids and tannins
latex

-food reserves:
-as sucrose or mineral salts, protein-storing vacuoles are common in seeds

waste products

Question 14

structure of centrioles

Answer 14

-made of two hollow cylinders
-each cylinder is made of nine triplets of microtubules
-the 2 cylinders are perpendicular to each other
-measures 0.4 µm

Question 15

function of centrioles

Answer 15

-organizes microtubules into spindle fibers

Question 16

microtubules function

Answer 16

-supports cell shape
-direct the movement of the organelles such as secretory vesicle