Unit 1 Flashcards

1
Q

6 levels of structural organization

A
  1. Chemical
  2. Cellular
  3. Tissue
  4. Organ
  5. System
  6. Organismal
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2
Q

What is the Chemical Level of organization

A

Atoms (the smallest units of matter) and molecules (2+ atoms joined together)

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3
Q

What is the Cellular Level of organization

A

Molecules combine to form cells (the basic structural and functional units of an organism that are composed of chemicals)

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4
Q

What is the Tissue Level of organization

A

Groups of cells and the materials surrounding them that perform a particular fxn

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5
Q

What is the Organ Level of organization

A

Composed of 2+ different types of tissues and have specific fxns and typically recognizable shapes

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6
Q

What is the System Level of organization

A

Consists of related organs with a common fxn

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7
Q

What is the Organismal Level of organization

A

All the parts of the human body functioning together

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8
Q

4 types of tissue

A
  1. Epithelial
  2. Connective
  3. Muscular
  4. Nervous
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9
Q

6 basic life processes

A
  1. Metabolism = catabolism & anabolism
  2. Responsiveness = body’s ability to detect and respond to changes
  3. Movement
  4. Growth = increase in body size that results from an increase in the size of existing cells, an increase in the # of cells or both
  5. Differentiation = the development of a cell from an unspecialized to specialized state
  6. Reproduction = formation of new cells OR production of new individual
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10
Q

Catabolism

A

Breakdown of complex chemical substances into simpler components

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11
Q

Anabolism

A

Building of complex chemical substances from smaller, simpler components

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12
Q

Homeostasis

A

A dynamic condition; the maintenance of relatively stable conditions in the body’s internal environment

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13
Q

Body fluids

A

Dilute, watery solutions containing dissolved chemicals that are found inside cells and surrounding them

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14
Q

2 types of fluid

A
  1. ICF (within cells)
  2. ECF (surrounds cells)
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15
Q

Interstitial fluid

A

ECF that fills the narrow spaces between the cells of tissues (e.g., blood plasma, lymph, synovial fluid)

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16
Q

How the cardiovascular system contributes to homeostasis

A

Transports O2 and nutrients through the body:
- O2 and nutrients diffuse into interstitial fluid via blood capillaries
- O2 and nutrients are taken up by cells and metabolized for energy
- During metabolization, cells produce waste which enter interstitial fluid and move across blood capillary walls into plasma
- Cardiovascular system transports waste to the appropriate organ for elimination to the external environment

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17
Q

2 regulatory systems to control homeostasis

A
  1. Nervous system
  2. Endocrine system
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18
Q

What does the nervous system do

A

Sends electrical signals (nerve impulses or action potentials) to organs that counteract (quick change)

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19
Q

What does the endocrine system do

A

Glands secrete messenger molecules called hormones into the blood (slow change)

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20
Q

Feedback systems (loops)

A

A cycle of events in which the status of a body condition is monitored, evaluated, changed, monitored, reevaluated, etc.

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21
Q

3 basic components of feedback systems

A
  1. Receptor
  2. Control center
  3. Effector
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22
Q

Receptor (afferent pathway)

A

body structure that monitors changes in a controlled condition and sends inputs to a control center

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23
Q

Control center (efferent pathway)

A

Sets the narrow range within which a controlled condition should be maintained, evaluates the input it receives from receptors, and generates output commands when they are needed

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24
Q

Effector

A

Body structure that receive outputs from the control center and produces a response or effect that changes the controlled condition

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25
Q

Negative feedback

A

Reverses a change in a controlled condition (regulate conditions that remain stable over long periods, e.g., blood pressure)

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26
Q

Positive feedback

A

Strengthens or reinforces a change in one of the body’s controlled conditions (reinforce conditions that don’t happen often, e.g., childbirth)

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27
Q

Anatomical position

A

Standard position of reference for regions of the body

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28
Q

Prone position

A

Lying face down

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29
Q

Supine position

A

Lying face up

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30
Q

6 principal regions of the body

A
  1. Head
  2. Neck
  3. Trunk
  4. Upper limbs
  5. Lower limbs
  6. Groin
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31
Q

Head (region)

A

Skull + Face

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32
Q

Trunk (region)

A

Chest, abdomen, pelvis

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33
Q

Upper limbs (region)

A

Attached to the trunk and includes the shoulder, armpit, arm (shoulder to elbow), forearm (elbow to wrist), wrist and hand

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34
Q

Lower limb (region)

A

Attached to the trunk and includes the buttock, thigh (buttock to knee), leg (knee to ankle), ankle and foot

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35
Q

Directional terms

A

Words that describe the position of one body part relative to another; most can be grouped into pairs that have opposite meanings

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36
Q

Superior

A

Towards the head or the upper part of a structure

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37
Q

Inferior

A

Away from the head, or the lower part of a structure

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38
Q

Anterior

A

Nearer to or at the front of the body

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39
Q

Posterior

A

Nearer to or at the back of the body

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40
Q

Medial

A

Nearer to the midline

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41
Q

Lateral

A

Farther from the midline

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42
Q

Intermediate

A

Btw 2 structures

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43
Q

Ipsilateral

A

On the same side of the body as another structure

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44
Q

Contralateral

A

On the opposite side of the body as another structure

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45
Q

Proximal

A

Nearer to the attachment of a limb to the trunk

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46
Q

Distal

A

Farther from the attachment of a limb to the trunk

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47
Q

Superficial

A

Toward or on the surface of the body

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48
Q

Deep

A

Away from the surface of the body

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49
Q

Planes

A

Imaginary flat surfaces that pass through body parts

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50
Q

Sagittal plane

A

Vertical plane that divides the body / organ into right and left sides:
1. Midsagittal plane (through the midline)
2. Parasagittal plane (not through the midline)

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51
Q

Frontal plane

A

Divides the body / organ into anterior and posterior portions

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52
Q

Transverse plane

A

Divides the body / organ into anterior and posterior portions

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53
Q

Oblique plane

A

Passes through the body / organ at on oblique angle

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54
Q

Sections

A

A cut of the body / organ made along one of the planes

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55
Q

Body cavities (4 overarching)

A

Spaces that enclose internal organs which are separated by bones, muscles and ligaments
1. cranial
2. vertebral
3. Thoracic
4. Abdominopelvic

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56
Q

Cranial cavity

A

A hallow space of the head composed of the cranial bones

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57
Q

Vertebral canal

A

Bones of the vertebral column (backbone)

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58
Q

Thoracic cavity (3 zones)

A

Formed by the ribs, muscles of the chest, sternum and thoracic portion of the vertebral column
1. pericardial cavity (x1) = around the heart
2. pleural cavities (x2) = around the lungs
3. mediastinum = btw the lungs

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59
Q

Abdominopelvic cavity (2 cavities)

A

From the diaphragm to the groin, encircled by the abdominal muscular wall and bones/muscles of the pelvis
1. Abdominal cavity
2. Pelvic cavity

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60
Q

Abdominal cavity

A

Contains: stomach, spleen, liver, gallbladder, small intestine, most of large intestine

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61
Q

Pelvic cavity

A

Contains: urinary bladder, some large intestine, organs of reproductive system

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62
Q

Membrane

A

A thin, pliable tissue that covers, lines, partitions or connects structures

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63
Q

Serous membrane

A

A double-layered membrane that covers the viscera within the thoracic and abdominal cavities and lines the walls of the thorax and abdomen and includes 2 parts:
1. Parietal layer
2. Visceral layer

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64
Q

Membrane of the thoracic cavity

A

2 serous membrane membranes:
1. Pleura = membranes of the pleural cavities
2. Pericardium = membrane of the pericardial cavity

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65
Q

Membrane of the abdominal cavity

A

1x serous membrane:
1. Peritoneum

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66
Q

3 components of non-living things

A
  1. Matter
  2. Mass
  3. Weight
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67
Q

Matter

A

Anything that occupies space and has mass

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68
Q

Mass

A

The amount of matter in any object

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69
Q

Weight

A

The force of gravity acting on matter

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70
Q

4 major chemical elements of the body

A
  1. Oxygen
  2. Carbon
  3. Hydrogen
  4. Nitrogen
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71
Q

8 lesser elements of the body

A
  1. Calcium
  2. Phosphorus (P)
  3. Potassium (K)
  4. Sulfur (S)
  5. Sodium (Na)
  6. Chlorine (Cl)
  7. Magnesium (Mg)
  8. Iron (Fe)
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72
Q

Atoms

A

Make up elements and are the smallest units of matter

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73
Q

Subatomic particles (3 types)

A

Make up atoms:
1. Protons
2. Neutrons
3. Electrons

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74
Q

Atomic number

A

The # of protons in the nucleus of an atom

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75
Q

Mass number

A

The sum of an atoms protons and neutrons

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76
Q

Isotopes

A

Atoms of an element that have different #’s of neutrons and therefore different mass numbers

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77
Q

Ions

A

An atom that has a positive or negative charge b/c it has unequal #’s of protons and electrons (e.g., Ca2+)

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78
Q

Molecule

A

When 2 or more atoms share electrons (e.g., O2, H2O)

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79
Q

Compound

A

A substance containing atoms of 2+ different elements (e.g., H2O, NaCl)

80
Q

Chemical bonds (3 types)

A

Forces that hold together the atoms of a molecule or compound, form when valence shell is chemically unstable
1. Ionic
2. Covalent
3. Hydrogen

81
Q

Ionic bonds

A

The force of attraction that holds together ions with opp. charges resulting in a gain or loss of electrons (e.g., NaCl)

82
Q

Covalent bonds

A

When 2+ share electrons rather than gaining or losing them

Types:
1. Non-polar = electrons shared equally (e.g., CH4)
2. Polar = electrons shared unequally (e.g., H2O)

83
Q

Hydrogen bonds

A

Result from attraction of opp. charged parts of molecules (weakest type)

84
Q

Surface tension

A

A measure of the difficulty of stretching or breaking the surface of a liquid

85
Q

Cohesion

A

The tendency of like particles to stay together (hydrogen bonds that link water molecules)

86
Q

3 types of energy

A
  1. Potential = energy stored in matter
  2. Chemical = energy stored in chemical bonds
  3. Kinetic = energy of motion
87
Q

Low of conservation of energy

A

The total amount of energy present at the beginning and end of a chemical rxn is the same. Although energy cannot be created or destroyed, it may be converted from one form to another

88
Q

Catalysts

A

Chemical compounds that speed up chemical reactions by lowering the activation energy needed for a rxn to occur (e.g., enzymes)

89
Q

5 types of chemical rxns

A
  1. Synthesis (anabolism)
  2. Decomposition (catabolism)
  3. Exchange
  4. Reversible
  5. Redox (transfer of electrons btw atoms/molecules)
90
Q

Inorganic compounds

A

Usually lack carbon + structurally simple (e.g., CO2, HCO3-, H2O)

91
Q

Organic compounds

A

Always contain carbon, always have covalent bonds

92
Q

Water

A

The most important abundant inorganic, polar compound in all living systems:
- Solvent (dissolves other substances)
- High heat capacity / heat of vaporization (requires a lot of heat to change state)
- Lubricant

93
Q

Hydrophilic

A

Water loving (polar)

94
Q

Hydrophobic

A

Water fearing (non-polar)

95
Q

Chemical rxns involving water (2 types)

A
  1. Hydrolysis = decomposition rxn involving water and breaks large molecules into smaller molecules
  2. Dehydration synthesis = when two smaller molecules join to form larger molecule(s) and water
96
Q

3 types of liquid mixtures

A
  1. Solution = small solute particles (transparent)
  2. Colloid = large solute particles (opaque)
  3. Suspension = contains solute particles that settle out + accumulate
97
Q

Buffer systems

A

Fxn to convert strong acids/bases in body fluids into weak acids/bases (weak acids/bases do not ionize easily) by adding / removing H+ and OH-

98
Q

5 types of organic compounds

A
  1. Carbs
  2. Lipids
  3. Proteins
  4. Nucleic acids
  5. ATP
99
Q

Macromolecule

A

Small organic molecules that combine into large ones (e.g., carbs, lipids, proteins, nucleic acids)

100
Q

Polymers

A

A large molecule formed by the covalent bonding of many identical or similar small building block molecules called monomers

101
Q

Carbohydrates (organic molecule 1)

A

Fxn = source of chemical energy to make ATP

Key elements = C, H, O

3 groups:
1. Monosaccharides (atoms)
2. Disaccharides (2 mono. joined via dehydration synthesis)
3. Polysaccharides (3+ mono. joined via dehydration synthesis)

e.g., sugar, glycogen, starch, cellulose

102
Q

Monosaccharide

A

Simple sugar composed of atoms; soluble in water

103
Q

Disaccharides

A

Simple sugar composed of 2 mono. via dehydration synthesis; soluble in water

104
Q

Polysaccharides

A

Composed of 3+ mono. via dehydration synthesis; insoluble in water; e.g., starch, cellulose

105
Q

Lipids (organic molecule 2)

A

Key elements = C, H, O

Groups:
1. Fatty acids
2. Triglycerids
3. Phospholipids
4. Steriods
5. Eicosanoids
6. Fat-soluble vitamins
7. Lipoproteins

106
Q

Fatty acids

A

Simplest lipid

Used to synthesize triglycerides and phospholipids or catabolized to generate ATP

2 types:
1. Saturated (completely saturated with H)
2. Unsaturated (not completely saturated with H)

107
Q

Triglycerides

A

Most plentiful lipid in the body + most highly concentrated form of chemical energy

Solid = saturated fat
Liquid = oil (monounsaturated or polysaturated)

108
Q

Phospholipids

A

Amphipathic (have polar and non-polar parts)

e.g., make up the plasma membrane of cells

109
Q

Steriods

A

4 rings of carbon atoms

E.g.,
- Cholesterol = cell membrane structure
- Estrogen/testosterone,
- Cortisol = blood sugar
- Bile salts = lipid digestion
- Vitamin D = bone growth

110
Q

Eicosanoids

A

Lipids derived from 20-carbon fatty acids

111
Q

Lipoproteins

A

A lipid-protein complex to help lipids become more soluble in blood plasma

112
Q

Proteins (organic molecule 3)

A

Large, complex molecules created from amino acids and polypeptides (chains of amino acids)

Key elements: C, H, O, N

Fxns:
- Catalytic: speed up rxns
- Structural: tissue, collagen, hair, skin
- Contractile: drive muscle contraction
- Immunological: acts as antibodies
- Transport: carry substances throughout body
- Regulatory: fun as hormones

113
Q

Denaturation

A

When a protein unravels and becomes non-functional

114
Q

Amino acids

A

Monomers (building blocks) of proteins, of which there are 20 types

115
Q

Enzymes

A

A protein molecule that acts as a catalysts in living cells (e.g., oxidases)

116
Q

Nucleic acids (organic molecule 4)

A

Huge organic compounds

Key elements = C, H, O, N, P

2 types:
1. Deoxyribonucleic acid (DNA)
2. Ribonucleic acid (RNA)

117
Q

DNA

A

Fxn: Encodes info to make proteins

Structure: Double stranded, A -> T, G -> C

Copying: Self-replicating

118
Q

RNA

A

Fxn: Carries the genetic code and helps make proteins

Structure: Single stranded, A -> U, G -> C

Copying: Made from DNA blueprint

119
Q

ATP (organic molecule 5)

A

Fxn: Energy of living systems in exergonic catabolic rxns

ATP+H2O->ADP+P+energy

ADP+P+energy->ATP+H2O

120
Q

Cells (3 main parts)

A

The basic, living, structural and functional units of the body
1. Plasma membrane
2. Cytoplasm
3. Nucleus

121
Q

Plasma membrane

A

The cell’s flexible outer surface, separating the cell’s internal and external environments (selective barrier + communicator)

122
Q

Cytoplasm

A

All cellular contents between the plasma membrane and the nucleus made of 2 key components:
1. Cytosol = intracellular fluid (ICF)
2. Organelles

123
Q

Nucleus

A

Organelle that houses most of a cell’s DNA

124
Q

Fluid mosaic model

A

Describes the plasma membrane as a continually moving sea of fluid lipids that contain a mosaic of proteins

125
Q

3 types of lipid molecules in the plasma membrane

A
  1. Phospholipids = 75%
  2. Cholesterol = 20%
  3. Glycolipids = 5%
126
Q

Phospholipids

A

Amphipathic molecules with a polar (hydrophilic) head and 2 non-polar (hydrophobic) tails

127
Q

4 membrane proteins

A
  1. Integral proteins
  2. Transmembrane proteins
  3. Peripheral proteins
  4. Glycocalyx
128
Q

Integral Membrane Proteins

A

Extend into or through the lipid bilayer and firmly embedded in it (amphipathic)

129
Q

Transmembrane proteins

A

Span the entire lipid bilayer and protrude into both the cytosol and extracellular fluid

130
Q

Peripheral proteins

A

Not firmly embedded in the membrane + support the plasma membrane, anchor integral proteins and participate in moving materials / organelles within cells

131
Q

Glycocalyx membrane proteins

A

A sugary coat made of the carbohydrate group of glycolipids and glycoproteins; varies from cell to cell and therefore acts as the molecular “signature” of cells for recognition

132
Q

6 functions of membrane proteins

A
  1. Ion channels
  2. Carrier (transporters)
  3. Receptors
  4. Enzymes
  5. Linkers
  6. Cell-identity markers
133
Q

What is meant by membrane fluidity

A

Membrane lipids and proteins easily rotate and move sideways in their half of the bilayer

Fluidity increases with double bonds & higher temperatures

134
Q

Membrane selective permeability

A

The plasma membrane permits some substances to pass more readily than others b/c of the non-polar hydrophobic interior

The lipid biyler of the plasma membrane is:
- highly permeable to non-polar molecules (O2, CO2)
- Moderately permeable to polar, uncharged molecules (H2O)
- Impermeable to ions and large, uncharged polar molecules (glucose)

135
Q

Transmembrane proteins

A

Act as channels and carriers to increase the plasma membrane’s permeability to ions and uncharged polar molecules that, unlike H2O and urea, cannot cross the lipid bilayer unassisted

136
Q

Plasma membrane electrical gradient

A

The inner surface of the plasma membrane is MORE negatively charged and the outer surface is MORE positively charged

137
Q

Plasma membrane concentration gradient

A

A difference in the concentration of a chemical, such as inside and outside the plasma membrane

138
Q

Electrochemical gradient of the plasma membrane

A

Combines influence of the concentration gradient and the electrical gradient to help move substances across the plasma membrane

139
Q

3 types of membrane transport

A
  1. Passive
  2. Active
  3. Vesciles
140
Q

Passive membrane transport

A

Substances move down their concentration / electrical gradient to cross the membrane via diffusion, using only its own kinetic energy from particles that are moving

3 types:
1. Simple diffusion
2. Facilitated diffusion
3. Osmosis

141
Q

What is simple diffusion

A

A passive process in which substances move freely through the lipid bilayer of the plasma membranes of cells without the help of membrane transport proteins

Substances transported:
- Nonpolar molecules: O2, CO2, fatty acids, steriods, fat-soluble vitamins
- Polar molecules: H2O, urea, alcohol

142
Q

What is facilitated diffusion

A

A passive process in which polar/highly charged substances move through the lipid bilayer via one of two integral membrane proteins:
1. Channel-mediated facilitated diffusion
2. Carrier-mediated facilitated diffusion

143
Q

Channel-mediated facilitated diffusion

A

A solute moves down its concentration gradient across the lipid bilayer through a membrane channel (e.g., K+ and Cl- or Na+ and Ca2+) at certain sites

Gated channels = when part of the channel protein acts as a plug, changing shape in one way to open the pore and in another way to close it

144
Q

Carrier-mediated facilitated diffusion

A

A passive process in which a carrier (or transporter) moves a solute down its concentration gradient across the plasma membrane (e.g., glucose, fructose, vitamins)

145
Q

What are the 3 steps of transporting glucose across the plasma membrane

A

Occurs via carrier-mediated facilitated diffusion
1. glucose binds to a specific type of carrier protein (glucose transporter - GluT) on the outside surface of the membrane
2. transporter undergoes a change in shape, glucose passes through the membrane
3. transporter releases glucose on the other side of the membrane

146
Q

Transport maximum

A

An upper limit on the number of carrier available in the plasma membrane to participate in carrier-mediated facilitated diffusion

Once all carrier are occupied the transport maximum is reached aka is fully saturated

147
Q

What is osmosis

A

A passive process by which water moves through a selectively permeable membrane from an area of lower solute concentration (i.e., higher water concentration) to an area of higher solute concentration (i.e., lower water concentration) via one of 2 methods:
1. Via simple diffusion
2. Via water channels + aquaporin integral membrane proteins

148
Q

What are the 3 types of solutions created via osmosis

A
  1. Isotonic = any solution in which a cell maintains its normal shape and volume
  2. Hypotonic (grow) = a solution that has a lower concentration of solutes
  3. Hypertonic (shrink) = has a higher concentration of solutes
149
Q

Tonicity

A

A measure of a solution’s ability to change the volume of a cell by altering its water content

150
Q

Lysis

A

The rupture of other types of cells due to placement in a hypotonic solution

151
Q

Define active membrane transport and what are the 2 types

A

An active process requiring energy (usually ATP) to allow carrier proteins (transmembrane proteins) to move solutes across the plasma membrane against a concentration gradient / electrical gradient

2 types:
1. Primary active transport
2. Secondary active transport

Substances transported:
- Polar / charged solutes

152
Q

What is primary active transport and what substances does it transport

A

Energy derived from hydrolysis of ATP changes the shape of a carrier protein, which “pumps” a substance across a plasma membrane against its con- concentration gradient

Substances transported:
- Na+, K+
- Ca2+, H+
- I-, Cl-
- Other ions

153
Q

What are the 4 steps of the sodium potassium pump

A

Objective: maintain a low concentration of Na+ and a high concentration of K+ in the cytosol

  1. 3 Na+ in cytosol bind to protein pump
  2. Binding triggers hydrolysis of ATP into ADP + P which causes a change in shape, expelling 3 Na+ into ECF
  3. 2 K+ bind and trigger release of P group from protein pump, triggers change in shape
  4. Reverts to original shape and releases 2 K+ into the cytosol and the cycle repeats
154
Q

What is secondary active transport and what substances does it transport

A

Coupled active transport of 2 substances across the plasma membrane using energy stored in a Na+ or H+ concentration gradient during primary active transport using anti ports and symports

  1. Antiporter: move Na+ (or H+) and another substance in opposite directions across the membrane
  2. Symporter: move Na+ (or H+ and another substance in the same direction across the membrane

Substances transported:
- Antiport: Ca2+, H+
- Symport: glucose, amino acids

155
Q

What is membrane transport using vesicles (3 types)

A

An active process in which tiny spherical membrane sacs transport substance into or out of cells using ATP
1. Endocytosis: into the cell
2. Exocytosis: out of the cell
3. Transytosis: Both

156
Q

What is endocytosis and what are the 3 sub-types

A

A transport vesicle used to move materials into a cell; includes 3 types:
1. Receptor-mediated
2. Phagocytosis
3. Bulk-phase (pinocytosis)

157
Q

What is receptor-mediated endocytosis and what are the 6 steps

A

A selective process by which cells take up specific ligands (molecules that bind to specific receptors) trigger infolding of a clathrin-coated pit that forms a vesicle containing ligands

Transported substances (ligands):
- Cholesterol
- Transferrin
- Vitamins
- Antibodies
- Hormones

6 steps:
1. Binding: LDL particle binds to plasma membrane from the ECF
2. Vesicle formation: Vesicle forms from invagination of the plasma membrane and pinches off
3. Uncoating: Cathrin-coated vesicle loses its coat and become uncoated
4. Fusion: vesicle fuses with an endoscope and LDL particles separate from their receptors
5. Recycling of receptors: receptors become transport vesicles that return to the plasma membrane
6. Degradation in lysosomes: lysosomes containing digestive enzymes break down large protein/lipid molecules of the LDL into amino acids, fatty acids and cholesterol

158
Q

What is phagocytosis endocytosis and how does it happen

A

“Cell eating” is a form of endocytosis in which the cell engulfs large solid particles into a cell after pseudopods engulf it to form a phagosome.

Examples:
1. Macrophages = in body tissues
2. Neutrophils = white blood cells

Transported substances:
- Bacteria
- Viruses
- Aged/dead cells

159
Q

What is bulk-phase endocytosis and what substances does it transport

A

“Cell drinking”; movement of ECF into a cell by infolding of plasma membrane to form a vesicle (does not involve receptors)

Substances transported:
- Solutes in ECF

160
Q

What is exocytosis and what substances does it transport

A

Movement of substances out of a cell in secretory vesicles that fuse with the plasma membrane and release their contents into the ECF

Substances transported:
- Neurotransmitters
- Hormones
- Digestive enzymes

161
Q

What is transcytosis and what substances does it transport

A

Movement of a substance through a cell as a result of endocytosis on one side and exocytosis on the opposite side

Substances transported:
- Antibodies across endothelial cells

E.g., substances btw blood plasma and interstitial fluid

162
Q

What is the cytoplasm of a cell and its 2 components

A

Consists of all the cellular contents between the plasma membrane and the nucleus

2 components:
1. Cytosol
2. Organelles

163
Q

What is the cytosol (ICF) of a cell, its purpose and structure

A

The fluid portion of the cytoplasm that surrounds organelles and contains dissolves/suspended components (e.g., ions, glucose)

Purpose:
The site of many chemical rxns required for cell existence

Structure:
Cytoskeleton = a network of 3 types of protein filaments that extends throughout the cytosol

164
Q

What are the 3 types of protein filaments that make up the cytoskeleton

A
  1. Microfilaments
  2. Intermediate filaments
  3. Microtubules
165
Q

What are microfilaments?

A

Thinnest protein filament of the cytoskeleton of a cell (aka cytosol) that:
1. generate movement
2. provide mechanical support to anchor cytoskeleton to integral proteins

166
Q

What are intermediate filaments?

A

Thickest protein filament of the cytoskeleton of a cell (aka cytosol) that:
1. stabilize the position of organelles
2. Help attach cells to one another

167
Q

What are microtubules?

A

Largest protein filament made of tubulin in the cytoskeleton of a cell (aka cytosol) that:
1. Help determine cell shape
2. help secretory vesicles move
3. include cilia and flagella

168
Q

What are organelles?

A

Specialized structures within the cytosol of a cell that have characteristic shapes, and they perform specific functions in cellular growth, maintenance, and reproduction

169
Q

What is a centrosome?

A

Microtubule organizing organelle of a cell, located near the nucleus

170
Q

What are cilia?

A

Short, hairlike projections (organelles) that extend from the surface of the cell and coordinate movement of fluid along the surface of a cell (e.g., in cells of the respiratory tract)

171
Q

What are flagella?

A

Long projections (organelles) that extend from the surface of a cell and move the cell (e.g., sperm cell tail)

172
Q

What is the endoplasmic reticulum? What are its 2 forms?

A

A organelle that is a network of membranes in the form of flattened sacs or tubules

2 forms:
1. Rough ER = continuous with nuclear membrane + studded with ribosomes  produces secretory proteins, membrane proteins and organellar proteins
2. Smooth ER = extends from the rough ER + no ribosomes  synthesizes fatty acids and steroids (estrogen and testosterone)

173
Q

What is the Golgi complex?

A

An organelle made of small flat membranous sacs called cisterns that accepts proteins / enzymes at the cis face / via transport vesicles from the rough ER and packages them into secretory, membrane or transport vesicles for delivery to their final destination via the trans face (exit)

174
Q

What are lysosomes?

A

An membrane-enclosed vesicles (organelle) that forms from the Golgi complex and degrades proteins delivered to them in vesicles

Fxns:
- Digest molecules that enter the cell via endocytosis
- Recycle cell structures/organelles during autophagy (regeneration)
- Destroy an entire cell during autolysis

175
Q

What are peroxisomes?

A

Organelles that contain oxidases, enzymes that can oxidize (remove hydrogen) from organic substances to prevent cell death and self-replication

E.g., found in the liver

176
Q

What are proteasomes?

A

Organelles that help with the continuous destruction of unneeded, damaged, or faulty proteins is the function of tiny barrel-shaped structures consisting of four stacked rings of proteins around a central core called

177
Q

What are mitochondria? What are their 4 main structures?

A

An organelle that generates most of the ATP through aerobic (oxygen-requiring) respiration and is self-replicating

4 structures:
1. External mitochondria membrane
2. Internal mitochondrial membrane
3. Mitochondrial cristae
4. Mitochondrial matrix

178
Q

What is the nucleus and its functions?

A

Consists of a nuclear envelope with pores, nucleoli and chromosomes which exist as a tangled mass of chromatin in interphase cells

Functions:
- Nucleus pores control the movement of substances btw the nucleus and cytoplasm
- Nucleoli produce ribosomes
- Chromosomes consist of genes that control cellular structures and direct cellular functions

179
Q

What is gene expression and name its 2 steps

A

Refers to the use of a gene’s DNA as a template for the synthesis of a specific protein and occurs in 2 steps
1. Transcription
2. Translation

180
Q

What is transcription?

A

The first step of gene expression; during which the information encoded in a specific region of DNA is transcribed (copied) to produce a specific molecule of RNA (ribonucleic acid) in the nucleus of a cell

Base pairs (DNA –> RNA):
A –> U
T –> A
G –> C
C –> G

181
Q

What are the 3 types of RNA made from DNA during transcription?

A
  1. mRNA = directs the synthesis of a protein
  2. rRNA = joins with ribosomal proteins to make ribosomes
  3. tRNA = binds to an amino acid and holds it in place on a ribosome until it is incorporated into a protein during translation
182
Q

What is RNA polymerase?

A

An enzyme that catalyzes transcription of DNA and attaches at the promoter (a special nucleotide sequence and the segment of DNA where transcription begins)

183
Q

What is a terminator in the context of transcription

A

A special nucleotide sequence where transcription of the DNA strand ends

When RNA polymerase reaches the terminator, the enzyme detaches from the transcribed RNA molecule and the DNA strand

184
Q

Compare introns vs. exons

A

During transcription, not all parts of a gene code for a protein:

Introns = regions within a gene that do not code for parts of proteins

Exons = the regions within a gene that do code for segments of a protein

185
Q

What is translation?

A

The second step of gene expression; a process when nucleotide sequence in an mRNA molecule specify the amino acid sequence of a protein, which is carried out by ribosomes in the cytoplasm

186
Q

What are the 7 steps of translation

A

Starts at the A site –> P site (where the chain is located) –> E

  1. An mRNA molecule binds to the small ribosomal subunit at the mRNA binding site
  2. The large ribosomal subunit attaches to the small ribosomal subunit–mRNA complex, creating a functional ribosome
  3. The anticodon of another tRNA with its attached amino acid pairs with the second mRNA codon at the A site of the ribosome
  4. A component of the large ribosomal subunit catalyzes the formation of a peptide bond between methionine and the amino acid carried by the tRNA at the A site
  5. Following the formation of the peptide bond, the resulting two- peptide protein becomes attached to the tRNA at the A site
  6. After peptide bond formation, the ribosome shifts the mRNA strand by one codon
  7. Protein synthesis ends when the ribosome reaches a stop codon at the A site, which causes the completed protein to detach from the final tRNA
187
Q

Polyribosome

A

When several ribosomes attached to the same mRNA during translation

188
Q

What is cell division? What are the 2 types?

A

The process by which cells reproduce themselves

2 types:
1. Somatic cell division
2. Reproductive cell division

189
Q

What is somatic cell division?

A

One of two types; When a cell undergoes a nuclear division called mitosis and a cytoplasmic division called cytokinesis to produce 2 genetically identical cells with the same # of chromosomes as the original cell

E.g., any cell of the body other than germ cells

190
Q

What is the cell cycle? What are the 3 main phases?

A

Mitosis: When a somatic cell duplicates its contents and divides in two (human cells, such as those in the brain, stomach, and kidneys, contain 23 pairs of chromosomes, for a total of 46)

Phases:
1. Interphase (G1, S, G2)
2. Mitosis M phase (prophase, metaphase, anaphase, telophase, cytokinesis)

191
Q

What is interphase?

A

The first step of the somatic cell cycle when a cell is not dividing but replicates its DNA and produces additional organelles and cytosolic components in anticipation for division

192
Q

What is mitosis (M phase)?

A

The second step of the somatic cell cycle when a cell is dividing and results in the formation of two identical cells, consists of a nuclear division (mitosis) and a cytoplasmic division (cytokinesis) to form two identical cells

193
Q

What is reproductive cell division?

A

One of two types; Consists of a special two-step division called meiosis, in which the number of chromosomes in the nucleus is reduced by half and produces gametes

194
Q

What is meiosis?

A

Sexual reproduction = the reproductive cell division that occurs in the gonads (ovaries and testes), produces gametes in which the number of chromosomes is reduced by half; genetic recombination occurs during meiosis

195
Q
A