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Biol 235 > Chapter 3: The Cellular Level of Organization > Flashcards

Chapter 3: The Cellular Level of Organization Flashcards

1
Q

The basic, living, structural and functional units of the body

the study of these is called cytology

A

Cells

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2
Q

Name the three main parts of a cell

A
  1. Plasma Membrane
  2. Cytoplasm
  3. Nucleus
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3
Q

The cells flexible outer surface that separates the internal environment from the external environment

A selective barrier that regulates the flow of materials in and out of the cell

Roll in communication among cells and between cells and external environment

A

Plasma Membrane

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4
Q

This part of a cell consists of all cellular contents between the plasma membrane and the nucleus

A

Cytoplasm

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5
Q

What are the two components of the cytoplasm?

A

Cytosol

Organelles

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6
Q

What is cytosol?

A

The fluid portion of cytoplasm (aka intracellular fluid)

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7
Q

What are organelles?

A

“little organs” inside the cell, each with a characteristic shape and specific function

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8
Q

What the cell part that is a large organelle that houses most of the cells DNA?

A

Nucleus

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9
Q

What is a chromosome?

A

A single molecule of DNA associated with several proteins

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10
Q

What does each chromosome contain?

A

Thousands of hereidtary units called genes

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11
Q

What do genes do?

A

Control most aspects of cellular structure and function

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12
Q

Define plasma membrane

A

A flexible, but sturdy, barrier that surrounds and contains the cytoplasm of a cell

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13
Q

What is the fluid mosaic model?

A

Where the arrangement of the plasma membrane resembles a continually moving sea of fluid lipids that contains a mosaic of many different proteins.

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14
Q

The basic strucural framework of the plasma membrane

A

Lipid bilayer

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15
Q

Describe the lipid bilayer

A

two back to back layers made up of phospholipids, cholesterol and glycolipids

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16
Q

What type of lipid makes up about 75% of the membrane?

A

Phospholipids

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17
Q

What does ampiphatic mean?

A

Having both polar and non-polar parts (lipids in bilayer)

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18
Q

This is the polar part of the phospholipid

It is hydrphyllic (love water)

The arrange on the outside layers of the plasma membrane, that way they are facing the watery fluids

A

Head

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19
Q

This is the non polar part of the phospholipid

It is hydrophobic

They point in towards the middle layer of the plasma membrane, away from watery fluids

A

tail made of two long fatty acids

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20
Q

This lipid is weakly ampiphatic and are spear among the other lipids in both layers of the membrane

The -OH group is the polar region and forms hydrogen bonds with the polar heads of the phospholipids and glycolipids

Stiff steroid rings and hydrocarbon tail are nonpolar; they fit among the fatty acid tails

A

Cholesterol

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21
Q

These have polar heads and nonpolar tails. Their heads are only found in the plasma membrane layer the is on the outer surface of the cell

A

Glycolipids

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22
Q

Integral proteins

A

extend through the lipid bilayer and are firmly embedded; most are transmembrane proteins and amphiphatic

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23
Q

Transmembrane proteins

A

proteins that span the entire lipid bilayer and protrude into both the cytosol and extracellular fluids; ampiphatic

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24
Q

Peripheral proteins

A

not firmly embedded; attached to the polar head of membrane lipids or to integral proteins at the inner or outer membrane surface

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25
Q

Integral proteins that have carbohydrate groupds attached to the ends that protrude into the extracellular fluid

A

Glycoproteins

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26
Q

An extensive sugary coat formed by the carbohydrate portions of glycolipids and glycoproteins

Varies from cell to cell

Hydrophylic and attracts a film of fluid that prevents cells from drying out

Used in immunity to recognize invader cells

A

Glycocalyx

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27
Q

Integral protein that specific ions can flow through to get in or out of a cell

A

Ion Channel Proteins

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28
Q

What does it mean if an ion channel is selective?

A

It only allows a single type of ion to pass through

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29
Q

These integral proteins selectively move substances from one side of the cell to the other by changing shape

A

Carrier proteins

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30
Q

Integral protein that serve as cell recognition sites. Specific to certain molecules called ligands

A

Receptor proteins

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31
Q

Integral proteins that catalyze a reaction inside or outside of a cell

A

Enzymes

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32
Q

Integral proteins that anchor proteins of neighboring cells to one another or to protein filaments inside and outside of the cell

A

Linker proteins

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33
Q

What type of molecules serve as cell identity markers?

A

glycoproteins and glycolipids

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34
Q

What two functions do cell-identity markers play a role in?

A
  1. Recoginition of other cells fo the same kind during tissue transformation
  2. Recognition and response by the immune system to potentially dangerous foreign cells
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35
Q

Allowing some substances to pass more readily than others through the plasma membrane

A

Selective permeability

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36
Q

What substances is the lipid bilayer portion of the plasma membrane HIGHLY permeable to?

A

Nonpolar molecules like oxygen, carbon dioxide, and steroids

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37
Q

What substances is the lipid bilayer portion of the plasma membrane MODERATELY permeable to?

A

small, uncharged polar molecules like water and urea

38
Q

What substances is the lipid bilayer portion of the plasma membrane IMpermeable to?

A

ions and large, uncharged polar molecules like glucose

39
Q

Difference in concentration of a chemical from one place to another

A

Concentration gradient

40
Q

Difference in electrical charges between two regions

A

Electrical Gradient

41
Q

The inner surface of the plasma membrane is more negatively charged and the outer surface is more positively charged; the charge difference is called this

A

membrane potential

42
Q

The combined influence of the concentration gradient and the electrical gradient on movement of a particular ion is called

A

Electrochemical gradient

43
Q

When a substance moves down its concentration or electric gradient to cross the membrane using only its own kinetic energy; no input of energy from the cell

A

Passive processes

44
Q

When cellular energy is used to drive the substance “uphill” against its concentration or electrical gradient; usually energy in form of ATP

A

Active processes

45
Q

When vesicles detach from the plasma membrane while bringing materials into a cell

A

endocytosis

46
Q

When vesicles merge with the plasma membrane to release materials from a cell

A

exocytosis

47
Q

Tiny spherical membranes that transport substances into and out of a cell

A

vesicles

48
Q

A passive process in which the random mixing of particles in a solution occurs becaues of the particles kinetic energy

Both the solute and the solvent undergo this process

A

Diffusion

49
Q

What does it mean to move down their concentration gradient?

A

Move to an area of high concentration to an area of lower concentration until evenly distributed

50
Q

5 factors that influence the diffusion rate of substances across the plasma membrane

A

1.Steepness of concentration gradient - greater differences, high rate of diffusion
2. Temperature - higher temp, faster rate
3. Mass of the diffusing substance - larger mass, slower rate
4. Surface area - larger membrane surface area, faster the rate
5. Diffusion distance - the greater distance, longer it takes

51
Q

Three types of diffusion

A
  1. Simple diffusion
  2. FAcilitated diffusion
  3. Osmosis
52
Q

A passive process in which substances (small, nonpolar, hydrophobic) move freely through the lipid bilayer of the plasma membranes of the cells without the help of membrane transport proteins

A

Simple Diffusion

* very important in movement of oxygen and carbon dioxide*

53
Q

A passive process of diffusion where an integral membrane protein (either carrier or membrane channel) assists a specific substance across the membrane.

A

Facilitated diffusion

54
Q

When a solute moves down its concentration gradient across the lipid bilayer through a membrane channel

Eg ion channel

A

Channel mediated facilitated diffusion

55
Q

What are the most numerous ion channels selective for in typical plasma membrane?

Fewer?

A

potassium K+
Chloride CL-

Fewer for Na+ and Ca+

56
Q

WHen a part of the channel protein acts as a plug or fate, changing shape in one way to open the pore and in another way to close it

A

Gated channel

57
Q

Facilitated diffusion where a carrier protein moves a solute down its concentration gradient across the plasma membrane

A

Carrier mediated facilitated diffusion

58
Q

Once all of the carrier proteins are occupied, the _____________ is reacher and a steeper gradient will not increase the rate of diffusion further

A

Transport maximum

59
Q

This energy source for making ATP, enters many cells by carrier-mediated facilitated diffusion

A

GLucose

60
Q

Process of glucose entering cells through carrier mediated facilitated diffusion

A
  1. GLucose binds to GluT (glucose transporter protein) on outside of cell
  2. Transporter protein changes shape and glucose passes through the membrane
  3. Glucose released on the other side of membrane
61
Q

This ligand works to elevate the transport maximum for facilitated diffusion of glucose into cells

A

insulin

62
Q

A type of diffusion in which there is net movement of a solvent (water) through a selectively permeable membrane from an area of higher water concentration to an area of lower water concentration; passive process

A

Osmosis

Moves through semipermeable membrane from an area of lower solute concentration to an area of high solute concentration

63
Q

Two ways water molecules pass through a plasma membrane

A
  1. Between phospholipid molecules via diffusion
  2. Moving through Aquaporins
64
Q

An integral membrane protein that function as water channels

Play a critical role in controlling the water content of cells

Responsible for the production of CSF, aqueous humor, tears, sweat, saliva and the concentration of urine

A

Aquaporin

65
Q

Pressure exerted by a liquid that that forces water molecules to move back to its original location

A

Hydrostatic pressure

66
Q

The force exerted by a solution with impermeable solute that is proportional to the concentration of the solute particles that cannot cross the membrane

A

Osmotic pressure

the higher the solute concentration, the higher the pressure

67
Q

The measure of a solutions ability to change the volume of cells by altering their water content

A

Tonicity

68
Q

A solution in which a cell maintains its normal shape and volume; concentration of solutes that cannot cross membrane are the same both in and outside of the cell

A

Isotonic solution

69
Q

A solution with a lower concentration of solutes than the cell; causes water to rush into the cell and the cell eventually bursts

A

Hypotonic; pure water is very hypotonic

70
Q

The bursting of cells by the exposure to a hypotonic solution, causing them to over fill with water and rupture

A

Lysis

For RBCs its called hemolysis

71
Q

A solution with a higher concentration that the inside of the cell

Causes water to rush out of cells and the cells shrink

A

Hypertonic

72
Q

The term for cells shrinking because of exposure to a hypertonic solution

A

Crenation

73
Q

Active process that allows some polar or charged colutes to move against their concentration gradient across a cell membrane; requires energy

A

Active transport

74
Q

Two sources of cellular energy needed for active transportation of molecules through carrier proteins

A
  1. Primary Active transport
  2. Secondary Active transport
75
Q

Active transport using energy from hydrolysis of ATP molecules

Energy changes the shape of the carrier protein which “pumps” a substance across the membrane against its concentration gradient

A

Primary Active Transport

76
Q

Active transport using energy stored in an ionic concentration gradient

A

Secondary Active Transport

77
Q

Carrier proteins that mediate primary active transport are called

A

Pumps

78
Q

The most prevalent primary active transport mechanism in the body?? Na+ K+

Part of this protein acts as an enzyme that hydrolyzes ATP

Maintain higher Na+ outside cell and higher K+ inside cell. These ions slowly diffuse back down their electrochemical gradients they need to be pumped back across

A

Sodium-potassium pump

aka Na+-K+ATPase

79
Q

This form of active transport uses energy stored in a Na+ of H+ concentration gradient to drive other substances across the membrane against their own concentration gradients.

Indirectly uses energy obtained from hydrolysis of ATP

A

Secondary active transport

80
Q

When a carrier protein binds to a sodium ion and another substance and then changes its shape so that both substances cross the membrane at the same time. What are the two types of transporter/ carrier proteins?

A

Symporters - both substances move to the same direction across the membrane

Antiporters - both move in opposite directions across the membrane

81
Q

Three types of endocytosis

A
  1. Receptor mediated endocytosis
  2. phagocytosis
  3. bulk-phase endocytosis
82
Q

A highly selective type of endocytosis by which cells take up specific ligands

A

Receptor-mediated endocytosis

83
Q

A form of endocytosis in which the cell engulfs large solid particles, like worn out cells, whole bacteria or viruses

A

Phagocytosis

84
Q

Two types of phagocytes (cells that can carry out phagocytosis) are called

A

Macrophages - located in many body tissues

Neutrophills - a type of WBC

85
Q

Projections of a phagocytes plasma membrane and cytoplasm that surround a particle outside the cell

A

Pseudopods

86
Q

The vesicle formed around the particle by the pseudopod of the phagocyte that fuses with lysosomes

A

Phagosome

87
Q

What happens when a phagosome containing a particle binds to one or more lysosome within a phagocyte?

A

Lysosomal enzymes break down the particles; any undigested materials remain indefinitely in a residual body vesicle and are either excreted through exocytosis or remain in the cell as lipofuscin granules

88
Q

What is pinocytosis (bulk phase endocytosis) and what is the process?

A

The taking up of tiny droplets of extracellular fluid into the cell

The cell membrane folds inwards and forms a vesicle containing the droplet of extracellular fluid; the vesicle pinches off and fuses with a lysosome in the cell where the contents are degraded by enzymes; the resulting smaller molecules leave the lysosome to be used elsewhere in the cell

THis occurs in most cells especially absorptive cells in intenstines and kidneys

89
Q

This process releases substances from within a cell using a vesicle

All cells do it, however most important for secretory cells and nerve cells

A

Exocytosis

90
Q

What do secretory cells use exocytosis to release from within?

A

Digestive enzymes, hormones, mucous, other secretions

91
Q

Why is it important for nerve cells to use exocytosis

A

They release neurotransmitters

92
Q

When vesicles undergo endocytosis on one side of a cell, move across the cell and then undergo exocytosis on the opposite side to release contents

A

Transcytosis

Occurs most often across epithelial cells that line blood vessels

Biol 235 (5 decks)

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