BIO 231 [Exam #1] > Lecture #2 > Flashcards

Lecture #2 Flashcards

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1
Q

What is the structure of the plasma membrane?

A

phospholipid bilayer that contains membrane proteins (integral & peripheral proteins)

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2
Q

What is the function of the plasma membrane?

A
  • provides barrier against substances outside the cell
  • determines which substances enter or leave the cell (membrane is selectively permeable)
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3
Q

Which membrane protein are firmly imbedded in the plasma membrane and help transport molecules across it?

A

integral proteins

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4
Q

Which protein is attached to the plasma membrane surface and support the plasma membrane from the cytoplasmic side?

A

peripheral proteins

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5
Q

Define simple diffusion

A

molecules move down their concentration gradient

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6
Q

Define osmosis

A

diffusion of water molecules across a membrane

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7
Q

Define facilitated diffusion

A

movement of molecules down their concentration gradient through an integral protein

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8
Q

Define active transport

A

integral proteins move molecules across the plasma membrane against their concentration gradient

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9
Q

All molecules want to move from a _______ concentration to a _________ concentration

A

high, low

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10
Q

Water wants to move to a _____________ solute concentration

A

higher

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11
Q

Water wants to move to a _____________ solute concentration

A

higher

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12
Q

What is crucial between cells and their surroundings to an organism?

A

water balance

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13
Q

Define tonicity

A

the tendency of a cell to lose or gain water in a solution

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14
Q

Describe an isotonic solution?

A

solute concentration is the SAME in the cell and in the solution (no osmosis occurs; cell volume remains constant)

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15
Q

What is a hypotonic solution?

A

solute concentration is greater in the cell than in the solution (cell gains water through osmosis - cell burst;lysed)

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16
Q

What is a hypertonic solution?

A

solute concentration is lower in the cell than in the solution (cell loses water through osmosis - cell shrivels)

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17
Q

What is exocytosis?

A

a mechanism that moves substances OUT of the cell (substance enclosed in vesicle -> vesicle migrates to the plasma membrane)

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18
Q

What is endocytosis?

A

mechanism by which particles ENTER cells

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19
Q

What are the types of endocytosis? Describe them

A
  • phagocytosis (cell eating)
  • pinocytosis (cell drinking)
  • receptor-mediated endocytosis (plasma proteins bind to certain molecules; invaginated and form coated pit, then pinches off to become a coated vesicle)
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20
Q

What method do insulin, other hormones, and enzymes enter cells?

A

receptor-mediated endocytosis

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21
Q

Describe cytoplasm

A
  • lies internal to the plasma membrane
  • consist of cytosol and organelles
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22
Q

Describe cytosol

A
  • jellylike fluid in which other cellular elements are suspended
  • consists of water, ions, and enzymes
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23
Q

What is the function of ribosomes? What does it act as?

A
  • site of protein synthesis (translation)
  • act as “assembly line”
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24
Q

Where do free ribosomes function?

A

within the cytosol

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25
Ribosomes that are attached to the ER make proteins...
- to renew plasma membrane - that are exported from the cell
26
Describe the endoplasmic reticulum
system of envelopes and tubes extending throughout the cytoplasm
27
What organelle has ribosomes on the external surface?
rough ER
28
What organelle consists of tubules in a branching network?
smooth ER
29
What is the function of the rough ER?
make proteins and digestive enzymes
30
What is the function of smooth ER?
- functions in lipid metabolism - makes/breaks down fats - stores calcium ions
31
What organelle is a stack of disc-shape cisterns (cavities)
golgi apparatus
32
What is the function of the golgi apparatus? What is it known as?
- sorts products of rough ER and sends them to proper destination - known as "packaging and shipping" division (ex. vesicle)
33
What organelle are sacs containing digestive enzymes?
lysosomes
34
What is the function of the lysosomes? What is it known as?
- digestive unwanted substances using digestive enzymes - known as the "demolition crew"
35
What organelle is surrounded by a double membrane?
mitochondria
36
What is the function of the mitochondria? What is it known as?
- generate most of the cell's energy in the form of ATP - known as "powerhouse of the cell"
37
What organelle are sacs of oxidase or catalase enzymes?
perioxisomes
38
What is the function of the peroxisomes? What are they known as?
- neutralize free radicals and break down poisons - break down long chains of fatty acids - known as "toxic waste removal system"
39
Which organs are there numerous amounts of peroxisomes?
liver and kidneys
40
Describe the cytoskeleton. What is it made up of?
- elaborate network of rods - made of: microfilaments (filaments of contractile protein actin), intermediate filaments (protein fibers), microtubules (cylindrical structures made of protein)
41
What is cilia used for? Where are they found?
- used for motility and feeding (works like rowing team) - found in respiratory tract
42
What is the function of flagella? Where is it found?
- propels organisms (works like a whip) - found on sperm cells
43
What are cilia and flagella composed of?
microtubules
44
Describe a centrosome. What is it composed of?
- spherical structure in the cytoplasm - composed of: centrosome matrix and centrioles
45
Describe centrioles. What do they consist of?
- paired cylindrical bodies - consists of: short microtubules
46
What acts in forming cilia, flagella, and the mitotic spindle?
centrioles
47
What is the function of the nucleus? What is it known as?
- contains DNA that directs the cell's activities - provides instruction for protein synthesis - known as "control center of cell"
48
What organelle has two membranes that are separated by fluid-filled space?
nuclear envelope
49
What is the function of nuclear pores?
allow large molecules to move in and out of the nucleus
50
What is the function of nucleolus? Where is it located and what is it known as?
- site of ribosome subunit assembly - located: in center of nucleus - known as: little nucleus
51
What is the first phase of INTERPHASE? What happens during this time?
- G1 Phase - make proteins and grow rapidly (cell metabolically active) - centrioles begin to replicate
52
What is the second phase of INTERPHASE? What happens during this time?
- S (synthetic) Phase - DNA replicates itself (ensures daughter cells receive identical copies of genetic material)
53
What is the last phase of INTERPHASE? What happens during this time?
- G2 Phase - centrioles are done copying themselves - enzymes needed for cell division are synthesized
54
What occurs in the M (mitotic) phase?
cells divide
55
What is mitosis?
division of the nucleus during cell division (chromosomes are distributed to the two daughter cells)
56
What is cytokinesis?
separation of one cell into two (occurs AFTER mitosis)
57
Name the stages of mitosis in order
PMAT - prophase - metaphase - anaphase - telophase
58
What occurs in PROPHASE?
- chromatin condenses into chromosomes - centriole pairs separate - mitotic spindle forms - nuclear membrane fragments
59
What occurs in METAPHASE?
chromosomes align along the equator
60
What occurs in ANAPHASE?
centromeres of chromosomes split
61
When does telophase begin?
when chromosomal movement stops
62
What occurs in TELOPHASE?
- chromosomes uncoil - resume threadlike extended-chromatin form - new nuclear envelope forms
63
If a growth factor is not released at the three major checkpoints, what will happen?
- the cell cycle will stop
64
What stages are growth factors released at?
- G1 Phase - G2 Phase - M Phase
65
What cells connect body parts or cover organs?
- fibroblast - epithelial cells - erythrocytes
66
What is the function of fibroblast?
makes and secretes protein component of fibers
67
What is unique about the shape of epithelial cells?
shape allows max. number of epithelial cells to pack together
68
What is unique about the shape of erythrocytes?
shape provides surface area for uptake of respiratory gases
69
What is the function of skeletal and smooth muscle cells?
move organs and body parts
70
What is the function of a fat cell?
stores nutrients
71
What is the function of a macrophage?
fights diseases (moves through tissue to reach infection sites)
72
What is the function of a neuron?
gathers information and controls body function
73
What is the function of sperm?
reproduction (long tail to swim to egg for fertilization)
BIO 231 [Exam #1]
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