Cells

Question 1

What Things Must a Cell do?

Answer 1

Manufacture cellular materials
Obtain raw materials
Remove waste
Generate the required energy
Control all of the above

Question 2

How many (approx.) Cells in Human Body

Answer 2

30 trillion.

Question 3

What is basically the ‘gatekeeper of the cell’

Answer 3

Plasma membrane

Question 4

What does semi-permeable barrier refer too in the Plasma memebrane

Answer 4

It allows some substances to pass through while blocking others.

Question 5

Saturated Plasma membrane is..

Answer 5

packed tightly
together, less fluidity

Question 6

Unsaturated Plasma membrane hydrophillic tails means

Answer 6

Tails are preventing tight
packing and there is more fluidity

Question 7

What does cholesterol help with Plasma membrane

Answer 7

Stabilises membrane fluidity for right fluidity

Question 8

Membranes decide the function of the protiens (True or false).

Answer 8

False, its the other way around

Question 9

Protiens in plasma membrane can have multipul functions (True or false)

Answer 9

True

Question 10

Membrane Proteins are involved in
Intercellular Joining (True or false)

Answer 10

True

Question 11

Membrane Proteins are involed with allowing cells to physically connect with protein structures outside the cell (True or false)

Answer 11

True

Question 12

Membrane Transport always requires energy (True or false)

Answer 12

False, there is passive (No energy) and Active (Needs energy) methods

Question 13

Signal transduction uses membrane proteins to relay
messages from outside the cell to inside the cell (True or false)

Answer 13

True

Question 14

The phospholipid bilayer forms an impermeable
membrane (True or false)

Answer 14

False (It is selectively permeable, not fully impermable) It is was, that would mean nothing could get into and out of cells making them mad useless

Question 15

Is Membrane transport for Large volumes or Smaller volumes

Answer 15

Smaller volumes

Question 16

Cholesterol stabilizes the fluidity of the membrane (True or false)

Answer 16

True

Question 17

Membrane transports that doesnt need energy

Answer 17

Passive

Question 18

Membrane transports that needs energy

Answer 18

Active transport

Question 19

Movement of molecules from high to low concentration with No energy (ATP) required. Happens due to random molecular motion.

Answer 19

Diffusion (Example: Oxygen moving into cells, carbon dioxide moving out.)

Question 20

Movement of molecules from high to low concentration (down the concentration gradient).
No energy (ATP) required.
Uses transport proteins (channel or carrier proteins) to help large or charged molecules cross the membrane.

Answer 20

Facilitated Diffusion
(Example: Glucose entering cells via a carrier protein)

Question 21

Movement of water across a cell membrane
requires channels called aquaporins. This process is called??

Answer 21

Osmosis
(Movement from a high water (low solute)
concentration to a low water (high solute)
concentration)

Question 22

Requires transport proteins, which are carriers that use
energy (ATP)

Answer 22

Active transport

Question 23

Indirect active transport.
One substance pumped across
the membrane and its concentration gradient
is used to power the movement
of a second substance against
its concentration gradient

Answer 23

Co-Transport

Question 24

In passive diffusion, molecules move against their
concentration gradient (True or false)

Answer 24

False

Question 25

Aquaporins are channels that allow water to cross the cell membrane (True or false)

Answer 25

True (Aquaporins literaly means water channel)

Question 26

Co-transport is indirect active transport because it does not require any energy

Answer 26

False, it does require energy

Question 27

______are bounded with a semi-permeable membrane which is dynamic and contains many proteins that have key functions.

Answer 27

Cells

Question 28

_____ are separate, specialised compartments within the cell.

Answer 28

Organelles

Question 29

What is the powerhouse of a cell

Answer 29

Mitochondria – Produces ATP (energy) through cellular respiration.

Question 30

Relaying messages from the external environment into the cell can best be described as A. Cell recognition B. Intercellular joining C. Signal transduction D. Adhesion to ECM

Answer 30

C. Signal Transduction

Question 31

Why are organelles membrane-bound

Answer 31

Membranes compartmentalize the cell, allowing specialized functions to occur in different organelles, maintaining efficiency and protecting reactions from interference.

Question 32

What is the plasma membrane made of

Answer 32

A phospholipid bilayer with embedded proteins, cholesterol, and carbohydrates.

Question 33

What sort of molecules can passively diffuse across the plasma membrane

Answer 33

Small, non-polar molecules like O₂, CO₂, and lipid-soluble molecules.

Question 34

What happens during co-transport of molecules

Answer 34

One molecule moves down its concentration gradient, driving the active transport of another molecule against its gradient using the same transport protein. (Push something out, then comes backs in together with other molecule)

Question 35

What are the key functions of membrane proteins

Answer 35

Transport – Channel/carrier proteins move molecules across the membrane. Signal transduction – Receptors relay messages from outside the cell. Cell recognition – Glycoproteins help immune system identify cells. Enzymatic activity – Membrane proteins catalyze reactions. Intercellular joining – Proteins link cells together.

Question 36

What some propeties of organelles

Answer 36

-Provide special conditions for specific processes. -Keep incompatible processes apart. -Allow specific substances to be concentrated. -Form concentration gradients. -Package substances for transport or export.

Question 37

Why Are Organelles membrane-bound

Answer 37

Because this Creates specialized compartments – Separates different cellular processes, preventing interference. -It Maintain specific conditions -It Increase efficiency

Question 38

Sperm looking ting's in Plasma Memebrane

Answer 38

Phospholipids (Each molecule has a hydrophilic (water-loving) head and hydrophobic (water-fearing) tails.)