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Biology > Unit 3: The Working Cell > Flashcards

Unit 3: The Working Cell Flashcards

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AP® Biology flashcards Biology 101 flashcards
1
Q

Why is the cell membrane called a fluid mosaic model?

A

The membrane is mosaic because it has diverse protein molecules embedded in a framework of phospholipids. It is fluid because most of the molecules can drift around the membrane

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2
Q

What makes the membrane fluid (why is good for the membrane) and what makes it mosaic?

A

Double bonds in the unsaturated fatty acid tails kid the phospholipids make kinks that prevent the phospholipids from packing tightly together, making it fluid this is good for the membrane because it stabilizes the membrane at warm temperatures and keeps it fluid a low temperatures.
The position of proteins in the phospholipid bilayer and their varied functions make it mosaic

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3
Q

What are the two main components of the cell membrane

A

Phospholipids and proteins

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4
Q

What is the role of cholesterol in the cell membrane?

A

Helps stabilize membranes at warm temperatures and keeps them fluid at low temperatures

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5
Q

Glycoproteins

A

Involved in cell to cell recognition

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6
Q

Integrins

A

Span the membrane, attach to the cytoskeleton and give the membrane a stronger framework

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7
Q

Enzymes

A

Work as a team to carry out reactions

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8
Q

Receptors

A

Has a shape that fits a specific messenger

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9
Q

Transport proteins

A

Helps certain molecules enter and exit the cell

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10
Q

Plasma membrane proteins

A

Form junctions between cells

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11
Q

What types of molecules can pass through the semi permeable membrane? Which types can’t?

A

Small, nonpolar molecules can pass

Large, polar molecules can’t

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12
Q

Diffusion

A

The tendency of particles to spread out evenly in spaces, moving from highly concentrated areas to low concentrated areas

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13
Q

Passive transport

A

The diffusion of a substance across a biological membrane

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14
Q

How does diffusion work in our lungs?

A

Diffusion down a concentration gradient is how oxygen enters red blood cells and carbon dioxide passes out of them

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15
Q

Why are oxygen and carbon dioxide able to easily diffuse across the membrane?

A

They are both nonpolar

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16
Q

What kind of molecules can not leave by diffusion? What helps them?

A

Ions and polar molecules. They can enter and leave if they are moving down their concentration gradients and have transport proteins

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17
Q

Osmosis

A

Diffusion of water molecules across a selectively permeable membrane

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18
Q

Solute

A

Substance being dissolved

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19
Q

Tonicity

What does it depend on?

A

The ability of a solution to cause a cell to gain or lose water
Depends on it’s concentration if solutes that can not across the plasma membrane relative to the concentrations of solutes in the cell

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20
Q

Facilitated diffusion

Does it require energy? What is the driving force?

A

When a protein helps move a substance down its concentration gradient
Does not require energy, the driving force is the concentration gradient

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21
Q

How does the number of transport proteins in a cell affect the rate of diffusion?

A

The greater number of transport proteins, the faster its rate of diffusion across the membrane

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22
Q

What types of substances need to use facilitated diffusion?

A

Sugars, amino acids, ions, water

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23
Q

What are aquaporins?

A

Transport proteins that make it possible to diffuse water in and out of certain cells quickly

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24
Q

Active transport

What molecule supplies energy for active transport?

A

Active transport expands energy in order to move a solute against its concentration gradient
ATP

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25
Q

Steps of active transport

A
  1. Solute binds to transport protein
  2. ATP transfers one of its phosphate groups to the transport proteins
  3. Protein changes shape so the solute is released in the other side of the membrane
  4. Phosphate group detaches and protein returns to its original shape
26
Q

What does active transport allow cells to maintain?

A

Allows them to maintain concentrations of small molecules that are different from concentrations of its surroundings

27
Q

Why is the sodium potassium pump important for nerve signaling?

A

Nerve signals depend on the concentration differences between potassium ions and sodium ions (higher K concentration inside cell and lower Na concentration ) the sodium potassium pump helps cells maintain the steep gradients by moving Na and K across the membrane against their concentration gradients

28
Q

Kinetic energy

A

Energy of motion

29
Q

Potential energy

A

Stored energy

30
Q

Chemical energy

A

Potential energy for a chemical reaction

31
Q

Thermodynamics

A

Study of energy transformations that occur in a collection of matter

32
Q

First and second law of thermodynamics

A
  1. The energy in the universe is constant

2. Energy conversions increase the entropy (disorder) of the universe

33
Q

Entropy

A

Measure of disorder

34
Q

Exergonic reaction

A

Chemical reaction that releases energy

35
Q

Endergonic reaction

A

Creates products rich in potential energy

36
Q

ATP

A

Adenosine triphosphate-powers nearly all forms of cellular work

37
Q

ADP

A

Adenine diphosphate-when bonds connecting phosphate groups become broken by hydrolysis and energy is released

38
Q

Phosphorylation

A

The hydrolysis of ATP releases energy by transferring the third phosphate group from ATP to another molecule

39
Q

Cofactors

A

Non protein helpers for enzymes

40
Q

Coenzymes

A

A cofactor that is an organic molecule

41
Q

Factors affecting fluidity

A
  • liquids ability to shift
  • temperature (hot=more fluid)
  • cholesterol
  • length of fatty acid (long=more immobile)
  • degree of saturation (unsaturated=more fluid)
42
Q

Glycoalyx

A

Layer of carbohydrates on extra cellular side

43
Q

Glycolipids

A

Attached to lipids

44
Q

Glycoprotein

A

Sugar attached to protein r

45
Q

Proteoglycons

A

Long sugars attached to proteins

46
Q

Isotonic

A

When the solute concentration of a cell and its environment are equal, so the cell gains and loses water at the same rate

47
Q

Hypotonic

A

A solution with a solute concentration lower than the concentration of the cell

48
Q

Hypertonic

A

A solution with a higher solute concentration

49
Q

What happens to an animal cell when it’s placed in a HYPOTONIC solution?

A

The cell gains water and lyses (bursts)

50
Q

What happens to an animal cell when it’s placed in a HYPERTONIC solution?

A

The cell shrivels and can die from water loss-crenation

51
Q

Why are water balance issues different in plant, prokaryote, and fungi cell?

A

Because they have a cell wall

52
Q

What happens when a plant cell is placed in an ISOTONIC solution?

A

It will be flaccid (limp)

53
Q

What happens when a plant cell is placed in a HYPOTONIC solution?

A

It becomes turgid (very firm) when water flows in

54
Q

What happens when a plant cell is placed in a HYPERTONIC solution?

A

The cell loses water and shrivels, the plasma membrane pulls away from the cell wall, a process called plasmolysis

55
Q

Importance of contractile vacuole in freshwater protists

A

Freshwater protists live in hypotonic environments and there is a constant net osmosis of water into the cell.The contractile vacuoles expel excess water, preventing the cell from bursting.

56
Q

Channel proteins

A

Molecules use these as a tunnel through the membrane

57
Q

Carrier proteins

A

Binds to its passenger, changes shape and releases its passenger on the other side

58
Q

Bulk transport

A

Transporting many substances in a vesicle at once

59
Q

Phagocytosis

A

“Cellular eating” takes in large molecules of cells

60
Q

Pinocytosis

A

“Cellular drinking” takes in dissolved solutes

61
Q

Receptor-mediated endocytosis

A

Receptor proteins for specific molecules are embedded in regions of the membrane that are lined by a layer of cost proteins

Biology (12 decks)

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