Chapter 2

Question 1

The first zygotic cellular divisions produce cells called______________

Answer 1

BLASTOMERE

Question 2

What is the thickness oof plasma membrane and in which microscope it is visible ?

Answer 2

7.5-10nm in thickness
Visible in electron microscopy

Question 3

Proteins in the plasma membrane ?

Answer 3

Integral proteins — embedded with lipid bilayer
Peripheral protein — associated in the surface ( cytoplasmic side )

Integral proteins which completly span bilayer is called transmembrane proteins

Question 4

What is aquaPorins?

Answer 4

Water molecules usually cross plasma membrane through water proteins called aqua Porins

Question 5

Diffusion, channels and most carrier proteins translocate sub- stances across membranes using only __________. In contrast, pumps are carrier proteins for active transport of ions or other
solutes and require energy derived from _______.

Answer 5

• Kinetic energy
• ATP

Question 6

Which Plasma membrane proteins that are linked to both cytoskeleton and ECM and allow the passage of material in both directions ?

Answer 6

Integrins

Question 7

What happens when cholesterol insert at phospholipid fatty acid chains ?

Answer 7

• restrict movement
• modulating fluidity of membrane components

Question 8

Which are Two types of vesicular transport ?

Answer 8

Endocytosis
Exocytosis

Question 9

When two cells make physical contact the signaling molecules are cell membrane proteins that bind to the receptor of target cells ?

a) endocrine signaling
b) autocrine signaling
c) paracrine signaling
d) juxtacrine signaling

Answer 9

Ans:) juxtacrine signaling

Question 10

3 important classes of receptor ?

Answer 10

Channel-linked receptor
Enzymatic receptor
G protein- coupled receptor

Question 11

What is the difference between endocytosis and exocytosis ?

Answer 11

ENDOCYTOSIS - macromolecules normally enter into the cells by forming folds within plasma membrane which fuse and pinch off internally forming cytoplasmic vesicles or vacuoles
EXOCYTOSIS - bulk movement of particles from inside to outside of the cell by fusion of secretary vesicles with plasma membrane
Eg: release of neurotransmitter by nerve cells

Question 12

WBCs engulfing bacteria which type of endocytosis is this ?

Answer 12

Phagocytosis

Question 13

Formation of small vesicles in capillary walls to move substances . Which type of endocytosis is this ?

Answer 13

Pinocytosis

Question 14

Example of receptor mediated cytosis ?

Answer 14

Uptake of cholesterol into cells

Question 15

Difference between Active and Passive process ?

Answer 15

• Active :- movement of substances requires expenditure of cellular energy
• Passive :- movement of substances down a concentration gradient requires kinetic energy , no cellular energy required and it continues till attaining equilibrium

Question 16

Explain the Different types of passive processes ?

Answer 16

Simple diffusion :- transport of small , non polar molecule down their concentration gradient across the selectively permeable membrane
Facilitated :- transport of ions and small polar molecules down their concentration gradient across a selectively permeable membrane by transport proteins
Osmosis :- diffusion of water; direction determined by relative solutes conc ; continues until equilibrium is reached

Question 17

Diff bet channel mediated and carries mediated ?give examples

Answer 17

Both are facilitated diffusion
Channel - movement of substances by channel proteins
Eg: Na+ influx
Carrier - movement of substances by carrier proteins
Eg: transport of glucose —-> cells by glucose carriers

Question 18

Movement of substance up its concentration gradient
in the same direction as Na*
Eg: Na*/glucose transport

Answer 18

Symport

Question 19

Movement of substance up its concentration gradient
in the opposite direction from Na*
Eg: Na/ H transport

Answer 19

Antiport

Question 20

Movement of substance up its concentration gradient;
powered directly by ATP

Answer 20

Primary active transport

Question 21

Example for primary active transport

Answer 21

Ca2* pumps transport Ca2* out of the cell
Na/K pump moves Na* out of cell and K*into cell

Question 22

chemical ligand diffuses in extracellular fluid but is rapidly metabolized so that its effect is only local on target cells near its source?

Answer 22

paracrine signaling

Question 23

special kind of paracrine inter- action, neurotransmitters act on adjacent cells through special contact areas called synapses

Answer 23

synaptic signaling

Question 24

signals bind receptors on the same cells that produced the messenger molecule

Answer 24

autocrine signaling

Question 25

signaling, important in early embryonic tissue interactions

Answer 25

Juxtacrine

Question 26

open associated channels upon ligand binding to promote transfer of molecules or ions across the membrane.

Answer 26

Channel - linked receptor

Question 27

Enzymatic receptor

Answer 27

Ligand binding promote catalytic activity in associated peripheral proteins

Question 28

G protein - coupled receptor

Answer 28

ligand binding stimulate associated G proteins which then bind the guanine nucleotide GTP and are released to activate other cytoplasmic proteins.

Question 29

•During protein synthesis many ribosomes typically bind the same strand of mRNA to form larger complexes called

Answer 29

Polyribosomes or polysomes

Question 30

Functions of ER ?

Answer 30

-ER function:- • Provide place for chemical reaction • Transport molecules from one cell to another ( away from cytoplasm ) • stores newly synthesized molecules • detoxification of alcohol and drugs

Question 31

major function of RER ?

Answer 31

The RER consists of saclike as well as parallel stacks of flattened cisternae Contains polyribosomes

Question 32

Vesicle movement through the Golgi apparatus is guided by specific coat proteins ?

Answer 32

COP2 and COP1

Question 33

Functions of SER ?

Answer 33

— Synthesis polypeptides and steroids — detoxifies potentially harmful exogenous molecules — sequestration and release of ca

Question 34

Golgi apparatus ?

Answer 34

Post translational modification of the proteins released from RER and packages and addresses these proteins to their proper determination

Question 35

Lysosomes remove excess or nonfunctional organel called ____

Answer 35

Autophagy

Question 36

Difference bet primary and secondary lysosomes ?

Answer 36

Primary :- emerge from the Golgi apparatus and contains inactive acid hydrolases specific for degrading the wide variety of cellular macromolecules Secondary :- fuse with the vesicles produced by endocytosis and contains material to be digested by the hydrolytic enzymes

Question 37

Functions of Mitochondria ?

Answer 37

Major site for ATP synthesis Abundant cytoplasm of cell where a large amount of energy is expended They are elongated organelles formed by the fission of preexisting mitochondria

Question 38

______ contains enzymes for β-oxidation of fatty acids and the citric acid (Krebs) cycle

Answer 38

Mitochondrial matrix

Question 39

the electron- transport system and ATP synthase

Answer 39

In the inner membrane of mitochondria

Question 40

Mitochondria of stressed cells may release ___________from the inner membrane, triggering a regulated series of events culminating in cell death (apoptosis)

Answer 40

cytochrome c

Question 41

Protein subunit of the microtubule ?

Answer 41

Heterodimer of alpha and beta tubulin

Question 42

Microtubules are arranged in larger and stable arrays called _____ ?

Answer 42

Axonemes

Question 43

In microtubules the polymerization of tubules is directed by ?

Answer 43

Microtubule organizing center’s (MTOCs)

Question 44

Cancer Chemoterapy

Answer 44

Block the activity of MS in rapidly growing NEOPLASTIC CELLS. DRUGS - vinblastine , vincristine , pacitaxel

Question 45

Keratinization

Answer 45

Cytokeratins accumulate during the differentiation ➡️keratinization Protect from minor abrasions. Produce hard protective structures for the skin eg; ( nails , feathers, beaks ,horns , scales of reptiles )

Question 46

pale brown granule found in many cells, especially in stable nondividing cells (eg, neurons, cardiac muscle),

Answer 46

Lipofuscin

Question 47

dense brown aggregate of denatured ferritin proteins with many atoms of bound iron, prominent in phagocytic cells of the liver and spleen, where it results from phagocytosis of red blood cells

Answer 47

Hemosiderin

Question 48

Hemosiderosis

Answer 48

Iron containing inclusion HEMOSIDERIN Occurs in cell of organs throughout the body Increased uptake of iron ⭕️extreme accumulations of iron in cellular hemosiderin can lead to disorders such as hemo- chromatosis and iron overload syndrome, in which tissues of the liver and other organs are damaged.

Question 49

intermediate filaments are stable, confer increased mechanical stability to cell structure, and are made up of different protein subunits in different cell types -True -False

Answer 49

True

Question 50

Contract and move cells; change cell shape; cytokinesis; cytoplasmic transport and streaming

Answer 50

Microfilaments

Question 51

Strengthen cell and tissue structure; maintain cell shape; maintain nuclear shape (lamins)

Answer 51

Intermediate filament

Question 52

__________is the most common class III intermediate filament protein and is found in most cells derived from embryonic mesenchyme

Answer 52

VIMENTIN

Question 53

__________are a family of seven isoforms present in the cell nucleus, where they form a structural framework called the nuclear lamina just inside the nuclear envelope

Answer 53

Lamins

Question 54

______________ proteins of three distinct sizes make heterodimers that form the subunits of the major inter- mediate filaments of neurons.

Answer 54

Neuro filaments

Question 55

Examples for vimentin like proteins ?

Answer 55

Desmin Glial fibrillar acidic protein (GFAP)

Question 56

Vimentin like proteins found in muscle cells

Answer 56

Desmin

Question 57

Desmin are Vimentin like proteins found in astrocytes , supporting cells of central nervous system tissue ✅ ❌

Answer 57

❌ Its GFAP