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AP Tignor 1 > Chap 3 > Flashcards

Chap 3 Flashcards

1
Q

Cells

A

Structural units of all living things

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2
Q

Amount of cells in the body

A

50-100 trillion

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3
Q

Explain the principle of complementarity of cells

A

Activities of cells are dictated by their shapes and by the types and numbers of subcellular structures they contain

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4
Q

Cells arise from

A

Other cells. Most body cells from mitosis,
Sex cells come from meiosis

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5
Q

What underlies every disease?

A

The loss of homeostasis in cells

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6
Q

Examples of the shape of cells

A

Disc shaped red blood cells, branching nerve cells, cube shaped cells of kidney tubules

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7
Q

Which cells connect body parts, form linings to transport gases?

A

Epithelial cells,
Fibroblasts,
erythrocytes

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8
Q

Which cells move organs and body parts?

A

Skeletal and smooth muscle cells

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9
Q

Which cells stores nutrients

A

Fat cell

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10
Q

Cells that fight disease

A

Macrophage

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11
Q

Cell that gathers information and controls body function

A

Nerve cells

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12
Q

Cell of reproduction

A

Sperm and eggs

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13
Q

Three main parts of a generalized cell

A

Plasma membrane
Cytoplasm
Nucleus

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14
Q

Plasma membrane

A

Outer boundary of a cell, acts as selectively permeable barrier

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15
Q

Cytoplasm

A

Intracellular fluid packed with organelles,

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16
Q

Organelles

A

Small structures that perform specific functions

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17
Q

Nucleus

A

Organelle that controls cellular activities

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18
Q

Extracellular materials

A

Substances contributing to body mass that are outside of the cells

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19
Q

Types of extracellular materials

A

Extracellular fluid
Cellular secretions
Extracellular matrix

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20
Q

Extracellular fluid includes

A

Interstitial fluid,
Blood plasma
Cerebrospinal fluid

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21
Q

Interstitial fluid

A

Body fluid filling the space surrounding cells, lymphatic capillaries and vascular

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22
Q

Function of ECF

A

Dissolves and transports substances in the body

Has amino acids, sugars, fatty acids, regulatory substances and wastes. Each cell extracts what it needs from the ECF

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23
Q

Cellular secretions

A

Aid in digestion
(Intestinal and gastric fluids)

Some act as lubricants (saliva, mucus, serous fluids)

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24
Q

Extracellular matrix

A

Most abundant extracellular material.
Jelly-like has proteins and polysaccharides.

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25
Q

Extracellular matrix function

A

Helps bind cells, most abundant in connective tissues

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26
Q

Plasma membrane

A

Phospholipids, cholesterol and proteins.. selectively permeable

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27
Q

What does the plasma membrane separate?

A

The extracellular fluid from the intracellular fluid

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28
Q

Fluid mosaic model thickness

A

7-10 nm

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29
Q

Fluid mosaic model

A

Proteins and cholesterol dispersed in the plasma membrane. Constantly changing.

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30
Q

Lipids in plasma membrane

A

Phospholipids
Cholesterol

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31
Q

Cholesterol functions in membrane

A

-Stiffens membrane
-decreases water solubility of membrane
-4 ring structure

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32
Q

Phospholipids functions

A

-Make basic structure of membrane
-Hydrophobic tails prevent water soluble elements from crossing

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33
Q

Proteins

A

-Determines which roles the membrane can do

-Transport, communication, receptors, attachment
different shapes have -different functions

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34
Q

Carbohydrates function in plasma membrane

A

-identify cells so they can sort themselves

-on outer surface of membrane. Like sugar covering a breakfast cereal

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35
Q

Glycocalyx

A

Covering of carbs on outer surface of cell membrane

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36
Q

Movement of phospholipids

A

Can move side to side but rarely flip over

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37
Q

Mobility of cholesterol

A

Can move easily to the other layer

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38
Q

Lipid anchor attaches to

A

Protein

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39
Q

Integral proteins

A

Embedded in lipid bilayer

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40
Q

Peripheral proteins

A

Anchored to membrane or to other proteins but not embedded in membrane

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41
Q

Glycoproteins

A

Carbs attached to proteins

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42
Q

Glycolypids

A

Carbs attached to lipids

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43
Q

Types of passive transport across plasma membrane

A
  1. Simple diffusion
    2.Facilitated diffusion
  2. Osmosis
  3. Filtration? Happens through capillary walls
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44
Q

Diffusion

A

Moving from high concentration to low concentration no energy. Try to make dispersion even

Depends on size and charge

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45
Q

Concentration gradient

A

Moving from high concentration to low concentration

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46
Q

Driving force for diffusion

A

Kinetic energy of molecules. Constant random high speed motion of molecules and ions. The molecules and ions clash into each other and push each other to help scatter particles

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47
Q

What affects speed of diffusion?

A

Concentration
Molecular size
Temperature

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48
Q

Explain how Concentration affects diffusion

A

When there’s a large concentration of molecules in one area, those in the concentrated area are more likely to collide. The collisions push them away

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49
Q

How does molecular size affect the rate of diffusion?

A

Smaller molecules diffuse more rapidly

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50
Q

Temperature

A

Higher temperature increases kinetic energy and causes the molecules to interact more rapidly, causing more diffusion to happen

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51
Q

When has a container reached equilibrium?

A

When the molecules are spread evenly throughout. No net movement molecules move evenly in all directions

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52
Q

Distance molecules travel during diffusion?

A

1/1000 of a page’s width

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53
Q

Examples of diffusion

A

Ions across cell membranes

Neurotransmitters between 2 nerve cells

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54
Q

What feature of the plasma membrane lets it be selectively permeable?

A

The hydrophobic core

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55
Q

Why is the selective permeability of a cell membrane important?

A

Let’s nutrients go in but keeps bad substances out.

Keeps important proteins in but let’s wastes go out

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56
Q

Facilitated diffusion

A

Moving with the help of transport proteins down the concentration gradient

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57
Q

Example of facilitated diffusion?

A

Water passing through aquaporins

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58
Q

Na K moves through or against concentration gradient?

A

Against

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59
Q

Active transport

A

Move using energy through membrane

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60
Q

Explain how NaK pump works?

A

Energy from ATP is used to move 3 Na ions out of cell and 2 K ions into cell.

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61
Q

Primary active transport

A

Uses ATP directly

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62
Q

Secondary active transport

A

Move chemicals against gradients using energy but doesn’t use ATP. I stead it uses downhill gradient from ion or molecule . Uses downhill gradient from one ion or molecule to drive uphill movement of another substance

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63
Q

Example of secondary active transport

A

Na & glucose into cell using cotransport ir symport.

Na ions move down gradient, glucose moves against concentration gradient

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64
Q

Exocytosis

A

Cells move substances from the intracellular fluid to the extracellular fluid using vesicles

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65
Q

Endocytosis

A

Membrane pinches in to create a vesicle

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66
Q

Ways to move materials across membranes

A

Active transport
Passive transport
Exocytosis
Endocytosis

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67
Q

Active process

A

Cell uses energy to move solutes across membranes

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68
Q

When are active processes used?

A

Substances too large, insoluble in lipids,
Move against concentration gradient

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69
Q

Types of active membrane transport

A

Active transport and vesicular transport

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70
Q

Difference between active transport and facilitated diffusion

A

Active transport Transports specific substances in reverse direction, needs energy

Facilitated diffusion always follows concentration gradients because it uses kinetic energy

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71
Q

Where does the energy in primary active transport come from?

A

Hydrolysis of ATP which powers pumps (transport proteins)

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72
Q

Secondary active transport energy source

A

Concentration gradients of ions made by primary active transport pumps. Always move more than one substance and use cotransport protein

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73
Q

Similarities between types of active transport

A

Primary and secondary active transport both transport specific substances
No transporter no transport

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74
Q

Explain primary active transport

A
  1. ATP gets hydrolysed and a Phosphate comes off
  2. Phosphate binds to the transport protein and gives it energy
  3. Transport protein changes shape and pumps bound solute across membrane
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75
Q

Examples of primary active transport systems

A

Calcium and hydrogen pumps

NaK pump

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76
Q

What is the pump protein for the sodium potassium pump?

A

Na+ -K+ ATPase

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77
Q

Explain the movement that happens thanks to the Na K pump

A

For every one ATP broken
Three Na+ go out of cell and two K+ go back in

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78
Q

Concentration of K+ in the cell is….

A

10x higher than outside, reverse is true of Na

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79
Q

Why is the difference in concentration in Na K important?

A

Let muscle cells and nerve cells function normally.

Let cells maintain fluid volume.

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80
Q

How does the Na K pump almost function continuously?

A

Na+ and K+ leak slowly but continuously through leakage channels down their concentration gradient, the Na+ -K+ pump operates almost continuously

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81
Q

Electrochemical gradients

A

Affect the way ions diffuse

82
Q

Explain secondary active transport

A

The pump stores energy by moving Na against it’s concentration gradient. Then like water held back by a dam, it can do work as it flows down. A substance moved across a membrane can do work as it leaks back. It drags substances back down

83
Q

Symport system

A

2 substances move in same direction

84
Q

Antiport system

A

2 substances move in opposite directions.

85
Q

Example of antiport system

A

Cotransporter used to regulate pH of cells

86
Q

Vesicular transport

A

Fluids containing large particles are transported via membranous sacs

87
Q

Transcytosis

A

Moves substances into, across then out of the cell.

88
Q

Where does transcytosis happen?

A

Endothelial cells lining blood vessels. Gets substances from blood into interstitial fluid

89
Q

Vesicular trafficking

A

Moves substances from one area or organelle to another part of the cell.

90
Q

What gives energy for vesicular transport?

A

ATP of Guanosine triphosphate

91
Q

How do receptors help endocytosis?

A

Receptors in membrane help determine substances to be transported

92
Q

Coated pit

A

Infolding of membrane. How vesicle starts to form. Coated with proteins

93
Q

Explain the steps of vesicular transport

A
  1. Coated pit ingests substance
  2. Protein coated vesicle detaches
  3. Coat proteins are recycled to plasma membrane
  4. Uncoated vesicle fuses with a sorting vesicle called an endosome
  5. Transport vesicle containing membrane components moves to the plasma membrane for recycling.
  6. Fused vesicle may fuse with a lysosome to destroy contents or deliver it’s contents to the plasma membrane on the opposite side of the cell
94
Q

Three types of endocytosis

A

1.Phagocytosis
2.Pinocytosis
3. Receptor mediated endocytosis

95
Q

Phagocytosis process

A

Cell eating
1. Cell engulfs large or solid material
2. Particle binds to surface receptors, pseudopods form around the particle (phagosome)

  1. Phagosome fuses with lysosome and contents are digested
96
Q

Phagocytes

A

WBCs that “eat” substances and destroy harmful materials

97
Q

Phagocytes move using _____ motion

A

Amoeboid

98
Q

Amoeboid motion

A

Changing shape
Flowing movement of cytoplasm to move across a surface

99
Q

Pinocytosis explain

A

“cell drinking”

Membranes folds around ECF with dissolved molecules

100
Q

Does pinocytosis happen in most cells?

A

Yes, nonselective way of sampling ECF

101
Q

In which cells is pinocytosis most important?

A

In cells that absorb substances like those in the intestines

102
Q

Explain why the area of the cell membrane remains constant?

A

Parts of membrane that make vesicles are recycled immediately using exocytosis after use

103
Q

Receptor mediated endocytosis

A

Lets specific things go in through endocytosis and transcytosis

  1. Receptors bind to substances and are taken in then dealt with
104
Q

Which substances are taken in through receptor mediated endocytosis

A

Enzymes, insulin, low density lipoproteins and iron

105
Q

What can hijack receptor mediated endocytosis?

A

Diphtheria
Flu viruses
Cholera

106
Q

Phagosome

A

Membranous sac made by plasma membrane

107
Q

Exocytosis caused by

A

Cell surface signals (a hormone binds)

Change in membrane voltage

108
Q

Uses of exocytosis

A

Hormone secretion
Neurotransmitter release
Mucus secretion
Ejection of wastes

109
Q

Secretory vesicle

A

Membranous sac that is protein coated, moves to cell membrane, fuses the ruptures

110
Q

Explain the process of exocytosis

A
  1. Membrane bound vesicle migrates to plasma membrane

2.proteins at vesicle’s (v and t snares) surface bind

  1. Vesicle and plasma membrane fuse and a pore opens up
  2. Vesicle contents are released to the cell’s exterior
111
Q

Explain docking of exocytosis

A

V-snares for vesicle recognize t-snares for target. Membranes corkscrew and fuse together, rearrange the lipid monolayers without fusing them

112
Q

Example of receptor mediated endocytosis

A

Intake or hormones, cholesterol, iron, most macromolecules

113
Q

Example of vesicular trafficking

A

Intracellular trafficking between certain organelles, endoplasmic reticulum, golgi apparatus

114
Q

Exocytosis examples

A

Secretion of neurotransmitters, hormones, mucus

115
Q

Permeability

A

The ability of molecules and ions to pass through a membrane

116
Q

Membrane potential

A

Voltage across a plasma membrane

117
Q

In which cells is membrane potential most important?

A

Nerve and muscle cells

118
Q

Voltage

A

Electrical potential energy resulting from the separation of oppositely charged particles. In cells oppositely charged particles are ions and what separates them is the plasma membrane

119
Q

Resting membrane potential + range

A

Voltage that exists across membrane during resting state of excitable cell

-50 to -90 mV

120
Q

Why are cells considered electrically polarized?

A

because even at resting state all cells have a charge that ranges from -50mV to -90mV

121
Q

The minus sign of a cell’s voltage indicates what?

A

inside of cell is negative compared to its outside

122
Q

voltage

A

charge separation

123
Q

where does differences of charges only occur?

A

At the membrane

124
Q

Describe the charges in the cytoplasm?

A

Charges in the cytoplasm are electrically neutral . they add up and cancel eachother out. Same with the ECF

125
Q

permeability

A

ability of ions and molecules to pass through a membrane

126
Q

Osmosis

A

diffusion through selectively permeable membrane by a solvent

127
Q

Why does the resting membrane potential exist?

A

diffusion causes ionic imbalances that polarize the membrane. active transport maintains the membrane potential.

128
Q

which concentration gradient mostly determines membrane potential?

A

concentration of K+ and the permeability of K+ to the membrane

129
Q

which anions predominate inside of body cells?

A

K+ and protein anions

130
Q

Extracellular fluid contains more of which ion?

A

Na+ balanced by Cl-

131
Q

The plasma membrane is somewhat permeable to K + but impearmeable to

A

protein anions.

132
Q

why is the cytoplasmic side of the membrane more negative?

A

k+ can diffuse out following its concentration gradient but the protein anions can’t and so their negative charges stay inside.

133
Q

Explain the steps of generating the resting membrane potential

A

K+ diffuses down the steep concentration gradient (out of the cell) via leakage channels, causing a negative charge on the inner face of the plasma membrane.

  1. K+ also moves back into cell because its attracted to the negative charge on the inner plasma membrane.
  2. A negative membrane potential (voltage) is created when the amount of K+ going out of cell equals the amount of K+ going into the cell. exiting K+ gradient directly opposes the gradient for K+ entry
134
Q

Why is membrane potantial largely determined by K+?

A

At rest, the membrane is much more permeable to K+ than Na+. The active transport of Na and K ions by the Na+ K+ pump maintains the concentration gradients

135
Q

In many cells, Na+ also contributes to resting membrane potential. Its resting membrane potential usually is -70 mV , but why is K more influential?

A

K+ diffuses through the membrane much more easier.

136
Q

Do you need a lot of ions to generate membrane potential?

A

no. the number of ions is small and does not change the concentrations in any way.

137
Q

In cells at rest, how many ions cross plasma membrane?

A

Very few. There is some net movement of K+ out of the cell and Na+ into the cell. Na+ is very strongly pulled in because of the concentration gradient and interior negative charge.

138
Q

How does active transport help maintain the membrane potential?

A

rate of active transport must be equal to the rate of diffusion of Na+ diffusion into the cell. If more Na+enters, more is pumped out. The pump maintains the membrane potential and the osmotic gradient. If too much Na+ stayed in the cell and wasn’t removed, the water would go in and the cells would burst.

139
Q

electrochemical gradient

A

The diffusion of particles happens because of differences in concentrations and because of electrical charges.

140
Q

Give an example of how the electrochemical gradient works?

A

the diffusion of K+ is helped by the concentration gradient but it is opposed by the electrical charges. the electrical charges pull it in but the concentration pushes it out.

The negative charges on the inner part of the cell membrane pull Na in but the impermeability limits Na diffusion

141
Q

What activates cells to carry out homeostatic functions

A

respond to extracellular chemicals, hormones, neurotransmitters, some cells interact with others

Extracellular molecules

142
Q

What percentage of membrane lipid is cholesterol?

A

20%

143
Q
A
144
Q

Polar region of cholesterol

A

Hydroxyl group

145
Q

Non polar region of cholesterol

A

Fused ring system

146
Q

Makes up halo the plasma membrane by mass and preforms most functions

A

Proteins

147
Q

Types of proteins on cell membrane

A

1.Transport
2.Receptors
3.Enzymes
4.cell-cell recognition (glycoproteins act as identity tags)
5. Attachment to cytoskeleton and ECM(extracellular matrix)
6. Cell to cell joining

148
Q

Transmembrane proteins

A

Go through membrane and peek out on both sides

149
Q

Types of transmembrane proteins

A

Channels, pores
Carriers,
Enzymes,
Receptors

150
Q

Protein pores

A

Opening of duct or sweat gland

151
Q

Glycocalyx and cancer

A

A cancerous cell’s glycocalyx might change almost continuously which lets it avoid the immune system

152
Q

Tight junctions

A

Impermeable
Form seals around cell
Prevent molecules from passing between cells

153
Q

Desmosomes

A
  1. Anchoring junctions
    2.bind adjacent cells like Velcro
    3.helps keep cells from tearing apart
154
Q

Gap junctions

A
  1. Communicating junctions
    2.lets ions and small molecules pass from cell to cell

3.important for heart and embryonic cells

155
Q

Give an example where tight junctions are used

A

The epithelial cells in the digestive tract are joined by tight junctions. Prevent digestive enzymes and microorganisms from going into bloodstream. Some ions can sometimes pass through

156
Q

“binding bodies”

A

Desmosomes

157
Q

Plaque

A

Buttonlike thickening on inner surface of plasma membrane

158
Q

Most important molecules cells use to interact with their environment

A

Cell adhesion molecules
Plasma membrane receptors

159
Q

CAMS

A

1.Cell adhesion molecules
2. Almost on every cell in body

160
Q

Function of CAMs

A

Embryonic development and wound repair
(Important where cell mobility is important)

161
Q

Sticky glycoproteins

A

Cadherins integrins

Types of CAMs

162
Q

Explain how CAMs work

A

1.Molecular Velcro that cells use to anchor themselves to other molecules in extra cellular space
2. Act as arms that help cells move against one another
3. Rally wbcs to infected or injured area
4. Transmit info about changes in extracellular matrix to cell. Bring a variety of responses like cell migration, proliferation, specialization

163
Q

Membrane receptors

A

Large and diverse group of integral proteins that serve as binding sites . Some do contact signaling, others chemical signaling, glycoproteins

164
Q

Contact signaling

A

Cells recognize each other. Important for immunity and development. Can be used by bacteria and others to identify target tissues

165
Q

Chemical signaling

A

Usually comes from outside of the cell

Happens when a ligand binds to a receptor and starts a response

166
Q

Ligands

A

Signaling chemicals that bind to membrane receptors

167
Q

Types of ligands

A

neurotransmitters, paracrines, hormones

168
Q

Paracrines

A

Chemicals that act locally and are rapidly destroyed

169
Q

How do different cells respond to the same ligand?

A

Differently. Acetylcholine stimulates skeletal muscle to contract but inhibits heart muscle.

170
Q

Why do target cells respond differently to the same ligand?

A

The reaction depends on the cell’s internal machinery.

171
Q

Explain how ligands work?

A

When a ligand binds to a receptor, the structure of the cell changes and proteins are altered in some way. For example the membrane proteins can become enzymes or they can open and close channels

172
Q

G protein coupled receptors

A

Exert effect through a G protein

173
Q

G protein

A

Relays signals between first (hormones or neurotransmitters)and second messengers (cAMP)
Helps activate or inactive a membrane-bound enzyme or ion channel

174
Q

The activation of G proteins leads to

A

Second messengers. Intracellular chemical signals that mediate cellular response

175
Q

cAMP and ionic calcium both activate

A

Protein kinase enzymes. Transfer phosphate groups from ATP to other proteins, activating a series of enzymes that cause the desired cellular activity

176
Q

Explain how G proteins work

A
  1. Ligand binds to receptor. Receptor changes shape and activates
  2. Activated receptor binds to G protein and activates it. Causes the release of GDP and bind GTP
  3. Activated G protein activates or inactives an effector protein by causing a shape change
  4. Activated effector enzymes catalyze reactions that produce second messengers in the cell
  5. Second messengers activate other enzymes or ion channels
  6. Kinase enzymes activate other enzymes. Transfer P from ATP to specific proteins. Activate a series of enzymes that trigger metabolic and structural changes in the cell
177
Q

Cytoplasm

A

Cellular material between plasma membrane and nucleus. Site of most cellular activities.

178
Q

Part of cytoplasm

A

Cytosol
Organelles
Inclusions

179
Q

Cytosol

A

Viscous,
Semitransparent fluid in which the other cytoplasmic elements are suspended.

Properties of both a colloid and a true solution

180
Q

Which things are dissolved in the cytosol

A

Water, proteins, salts, sugars, others

181
Q

Inclusions

A

Chemical substances that may or may not be present. Include stored nutrients, glycogen granules, lipid droplets in fat cells , pigment granules in skin and hair

182
Q

Organelles

A

Metabolic machinery of cells

183
Q

Which organelles lack a membrane

A

Ribosomes and centrioles

184
Q

Why do membranous organelles need a membrane

A

To maintain a different internal environment than the surrounding cytosol

185
Q

Threadlike or lozenge shaped organelles

A

Mitochondria

186
Q

Active cells have more clusters of

A

Mitochondria

187
Q

Mitochondria

A

ATP generation for cellular activities

188
Q

Describe the structure of a mitochondrion?

A

Two membranes. Inner membrane folds and makes cristae. Folds make contact with matrix. Gel-like substance within the mitochondrion.
Enzymes within matrix break down intermediate products of food fuels (Glucose and others) to water and CO2

189
Q

Important components of of mitochondria that let them reproduce themselves?

A

DNA, RNA, ribosomes.

190
Q

What directs the synthesis of proteins needed for mitochondrial function?

A

Mitochondrial genes 37 make 1%
Cell’s nucleus makes 99%

191
Q

Fission

A

Mitochondria synthesize more cristae or pinch in half to increase their number and then grow their size

192
Q

Ribosomes

A

Sites of protein synthesis. Has two subunits. Made of proteins and RNAs

193
Q

Free ribosomes

A

Float freely in cytosol.
Make soluble proteins that work in cytosol, as well as those imported into mitochondria and other organelles

194
Q

Membrane bound ribosomes

A

Attached to membranes. Form rough ER. Make proteins that are going to be incorporated into membrane or lysosomes or exported out of cell

195
Q

Crenation

A

Water goes out of cell because it’s in a hypertonic solution

196
Q

Endoplasmic reticulum

A

System of interconnected tubes and parallel sacs called cisterns. Cisterns are filled with fluid

197
Q

Continuous with outer membrane and accounts for half of the cell’s membranes

A

ER

198
Q

Rough endoplasmic reticulum

A

Studded with ribosomes
Makes proteins that go to golgi apparatus

199
Q

Functions of rough ER

A
  1. Makes secretory proteins. Abundant in antibody producing cells, liver cells. Make blood proteins
  2. Membrane factory. Integral proteins and phospholipids are manufactured. Makes glycoproteins
200
Q

Enzymes that catalyse lipid synthesis have their active sites on

A

External (cytosolic) face of ER membrane where needed substrates are available.

201
Q

RAS

A

Most frequently mutated genes in human cancer.

family of genes that regulate cell growth and division. mutations can cause cancer

202
Q

Myc

A

AP Tignor 1 (29 decks)

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