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Question 1

A typical cell formed by two major parts:

Answer 1

the nucleus and the cytoplasm.

Question 2

The nucleus is separated from the cytoplasm by a_________

Answer 2

nuclear membrane.

Question 3

The different substances that make up the cell are collectively called________

Answer 3

protoplasm

Question 4

Most organelles of the cell are covered by membranes composed primarily of _______ and _______.

Answer 4

Lipids
Proteins

Question 5

The cell membrane which envelops the cell, is a thin,
pliable, elastic structure only ___________ nanometers thick.

Answer 5

7.5 to 10

Question 6

cell membrane is composed almost entirely of proteins and lipids (proteins 55%; phospholipids 25%; cholesterol 13%; other lipids 4% and carbohydrates 3% ).
T/F

Question 7

The basic structure of cell membrane is a lipid bilayer, which is a thin, double-layered film of lipids.
T/F

Answer 7

T

Question 8

The lipid layer of the membrane is ______________ to the usual water-soluble substances, such as ions, glucose, and urea.

Answer 8

Impermeable

Question 9

fat-soluble substances, such as oxygen, carbon dioxide, and alcohol, can penetrate this portion of the membrane with ease.
T/F

Answer 9

T

Question 10

There are globular masses floating in the lipid bilayer. These are
membrane proteins, most of which are _____________

Answer 10

glycoproteins.

Question 11

Two types of proteins are present in the cell membrane :

Answer 11

1. integral proteins that protrude all the way through the membrane.
2. peripheral proteins that are attached only to one surface of the membrane and do not penetrate all the way through.

Question 12

Integral proteins provide ________________ through which water molecules and water-soluble substances, especially ions, can diffuse between the extracellular and intracellular fluids.

Answer 12

Structural channels (or pores)

Question 13

integral proteins act as _____________ for transporting substances that otherwise could not penetrate the lipid bilayer.

Answer 13

carrier proteins

Question 14

Sometimes integral proteins even transport substances in the direction opposite to their natural direction of diffusion, which is called ____________

Answer 14

“active transport.”

Question 15

integral membrane protein act as

Answer 15

enzymes

Question 16

Integral membrane proteins can also serve as a __________ for water-soluble chemicals, such as ______________, that do not easily penetrate the cell membrane.

Answer 16

receptors

peptide hormones

Question 17

integral proteins spanning the cell membrane provide a means of conveying ____________ about the environment to the cell interior.

Answer 17

information

Question 18

Peripheral protein molecules are often attached to the integral proteins, their function almost entirely as ____________ or as ___________of transport of substances through the cell membrane “pores.”

Answer 18

enzymes

controllers

Question 19

Membrane carbohydrates occur almost invariably in
combination with proteins or lipids in the form of:

Answer 19

i. Glycoprotein.
ii. Glycolipids.

Question 20

The entire outside surface of the cell often has a loose carbohydrate coat called the__________

Answer 20

glycocalyx

Question 21

The carbohydrate moieties attached to the outer surface of the cell have several important functions:

Answer 21

‏1- has negative charge that repels other negative objects
2- the glycocalyx attaching one cell to another
3- many carbohydrates act as receptor for binding hormones such as insulin
4- some carbohydrates moisties enter into immune reactions

Question 22

____________ It’s a network of tubular and flat vesicular structures in the cytoplasm.

Answer 22

Endoplasmic Reticulum

Question 23

Endoplasmic Reticulum:
A-It’s a network of tubular and flat vesicular
structures in the cytoplasm.
B-The tubules and vesicles interconnect with one another.
C-their walls are constructed of lipid bilayer membranes that contain large amounts of proteins.
D-The space inside the tubules and vesicles is filled with endoplasmic matrix, a watery medium.
E-all of them true

Answer 23

E

Question 24

Golgi Apparatus is prominent in _________ cells

Answer 24

Secretory

Question 25

The transported substances are then processed in the Golgi apparatus to form:

Answer 25

I. Lysosomes. II. Secretory vesicles. And III. Other cytoplasmic components

Question 26

The lysosomes provide an intracellular _________ system

Answer 26

digestive

Question 27

The lysosomes provide an intracellular digestive system that allows the cell to digest:

Answer 27

(1) Damaged cellular structures. (2) Food particles that have been ingested by the cell. (3) Unwanted matter such as bacteria.

Question 28

A _________________ is capable of splitting an organic compound into two or more parts (protein, glycogen, and lipids).

Answer 28

A hydrolytic enzyme

Question 29

Almost all such secretory substances are formed by the:

Answer 29

endoplasmic reticulum–Golgi apparatus system.

Question 30

___________Without them, cells would be unable to extract enough energy from the nutrients.

Answer 30

Mitochondria

Question 31

Mitochondria are present in all areas of each cell’s cytoplasm, but the total varies from less than a _____________ up to ___________, depending on the amount of energy required by the cell.

Answer 31

less than a hundred up to several thousand

Question 32

Transport of substances through the cell membrane: two ways

Answer 32

1. Diffusion. 2. Active Transport.

Question 33

_______________that causes the substance to move against an energy gradient, such as from a low-concentration state to a high-concentration state.

Answer 33

Active transport:

Question 34

Diffusion Through the Cell Membrane It divided into two subtypes called:

Answer 34

Simple diffusion and facilitated diffusion.

Question 35

The protein channels are distinguished by two important characteristics:

Answer 35

(1) They are often selectively permeable to certain substances, (2) Many of the channels can be opened or closed by gates.

Question 36

inner surfaces of sodium channel are strongly negatively charged. T/F

Answer 36

T

Question 37

potassium channels are slightly smaller than the sodium channels, only _________nanometer

Answer 37

0.3 by 0.3

Question 38

The opening and closing of gates are controlled in two principals:

Answer 38

1. Voltage gating. 2. Chemical (ligand) gating:

Question 39

Facilitated diffusion is also called

Answer 39

carrier-mediated diffusion

Question 40

Among the most important substances that cross cell membranes by facilitated diffusion are ___________ and most of the ____________.

Answer 40

glucose amino acids

Question 41

Active transport is divided into two types according to the source of the energy used to cause the transport.

Answer 41

1. primary active transport 2. Secondary active transport

Question 42

When a cell membrane moves molecules or ions against a concentration gradient or against an electrical gradient or pressuregradient theprocess is called _______________

Answer 42

activetransport

Question 43

Different substances that are actively transported through some cell membranes include:

Answer 43

sodium ions, potassium ions, calcium ions, iron ions, hydrogen ions, chloride ions, iodide ions, urate ions, several different sugars, and most of the amino acids.

Question 44

The carrier protein has the followings:

Answer 44

1. It has three receptor sites for binding sodium ions on the portion of the protein that protrudes to the inside of the cell. 2. It has two receptor sites for potassium ions on the outside. 3. The inside portion of this protein near the sodium binding sites has ATPase activity.