Chapter 3 Definitions Flashcards
1
Q
What forms the outer boundary of a cell?
A
Plasma or cell membrane
2
Q
Organelles are _____________?
A
Specialized structures that perform specific functions
Example-The nucleus is an organelle
3
Q
Cytoplasm is?
A
located between the nucleus and plasma membrane and contains many organelles
4
Q
What is cell metabolism?
A
The chemical reactions that occur with cells
5
Q
What are intracellular substances?
A
Substances inside the cell
6
Q
What are extracellular substances?
A
Substances outside the cell
7
Q
What does intercellular mean?
A
Between cells
8
Q
What are the predominate lipids of the plasma membrane?
A
Phospolipids and cholesterol
9
Q
Phospholipids assemble?
A
The lipid bi-layer
10
Q
What is the modern concept of the plasma membrane called?
A
the fluid mosaic model
11
Q
What do marker molecules do?
A
Allow cells to identify one another or other molecules
12
Q
What are most marker molecules?
A
glycoproteins or glycolipids
13
Q
What are glycoproteins?
A
Portions with an attached carbohydrate
14
Q
What are glycolipids?
A
Lipids with an attached carbohydrate
15
Q
What do attachment proteins do?
A
Allow cells to attach to other cells or to extracellular molecules
16
Q
What are cadherins?
A
proteins that attach cells to other cells
17
Q
What are integrins?
A
proteins that attach cells to extracellular molecules
18
Q
What are transport proteins?
A
Proteins that extend from one surface of the cell to the other, and move ions and molecules across plasma membrane
19
Q
What are membrane channels?
A
Chanel proteins that are like small pores that extend from one surface of the membrane to the other
20
Q
What are receptor proteins?
A
Proteins or glycoproteins with an exposed receptor site on the outer surface
21
Q
What does selectively permeable mean?
A
Allowing some substances but not others to pass
22
Q
What is the tendency for ions and molecules to move from an area of higher concentration to an area of lower concentration?
A
Diffusion
23
Q
What is a solution?
A
Any mixture of liquid, gases, or solids which the substances are uniformly distributed with no clear boundary between substances
24
Q
The _________ dissolves in the _____________.
A
The solute dissolves in the solvent
25
What is the concentration gradient?
The concentration difference between two points divided by the distance between two points
26
What is osmosis?
Movement of water across a selectively permeable membrane such as a plasma membrane
27
In some cells, rapid water movement through a plasma membrane occurs through ________ or ___________.
Water channels, or aquaporins
28
What is osmotic pressure?
Force required to prevent the movement of water by osmosis across a selectively permeable membrane
29
Hydrostatic pressure is?
When a solution rises, the weight of a column of water in the tube produces hydrostatic pressue
30
What are Isomtic solutions?
Solutions with the same concentration of solute particles and the same osmotic pressure.
31
What is hyperosmotic solutions?
The solution with a greater concentration of solute particles and greater osmotic pressure
32
What is a hyposmotic solution?
The more diluted solution with the lower osmotic concentration
33
What occurs when a cell is placed in a hypotonic solution?
Water moves into the cell, and can cause the cell to lysis (swell)
34
If a cell is in a isotonic solution what will happen?
Nothing, the concentration of solutes are the same
35
What occurs when a cell is placed in a hypertonic solution?
Water moves out of the cell, resulting in cell shrinkage
36
What is mediated transport?
Process in which transport proteins mediate or assist in the movement of ions and molecules across the plasma membrane
37
What does specificity refer to?
Each transport protein moves particular molecules or ions but not others
38
When does competition occur?
When similar molecules or ions can be moved by the transport protein
39
When does saturation occur?
When the rate of movement of molecules or ions across the membrane is limited by the number of available transport protiens
40
What forms membrane channels?
Channel proteins
41
What are membrane channels that transport ions?
Ion channels
42
Carrier protiens/transporters are?
Membrane proteins that move ions or molecules from one side of the plasma membrane to the other
43
What is uniport?
Uniport is the movement of one specific ion or molecule across the membrane
44
Symport is?
Movement of two or more different ions or molecules in the same direction across the plasma membrane
45
What is antiport?
Movement of two or more different ions or molecules in opposite directions across the plasma membrane
46
Carrier proteins can be classified into 3 categories, what are they?
uniporters, symporters, and antiporters
47
Movement of ions or molecules by uniporter is often called __________ ______________.
Facilitated diffusion
48
What are ATP-power pumps?
Transport proteins that use energy derived from from the breakdown of ATP to move ions and molecules from one side of the plasma membrane to the other
49
The movement of ions and molecules by ATP-powered pumps is called ______ transport.
Active
50
What is a vesicle?
A membrane bound sac that surrounds substances within the cytoplasm of cells
51
What is vesicular transport?
Movement of materials by vesicles into, out of, or within cells
52
What is vesicular transport into cells called?
endocytosis
53
When the plasma membrane contains receptors that bind to specific molecules it is called?
Receptor-mediated endocytosis
54
What accumulates materials for release from cells?
Secretory Vessels
55
What is the cytoplasm?
Cellular material outside the nucleus but inside to plasma membrane
56
What are microtubules?
Hollow structures formed from protien subunits
57
Actin filaments/microfilaments are what?
small fibrils formed from protein subunits that form bundles, sheets, or networks in the cytoplasm of cells
58
What are intermediate filaments?
fibrils formed from protein subunits that are smaller in diameter than microtubules but larger in diameter then microfilaments
59
What does the cytosol include?
| What is it?
The cytosol includes cytoplasmic inclusions, which are aggregates of chemicals either produced by the cell or taken in by the cell
60
What are structures within the cell that specialize in particular functions?
Organelles
61
What separates the nucleus from the cytoplasm?
Nuclear envelope
62
Through what structure do material pass in and out of the nucleus?
How is this structure formed?
Nuclear pores.
| They are formed when the inner and outer membranes of the nuclear membrane come together
63
Deoxynribonucleic acid is found where?
In the nucleus
64
What are histones?
Proteins that are important to the structural organization of DNA
65
What are chromatin?
When the chromosomes are are dispersed through nucleus as delicate filaments
66
Each chromosome consists of two ____________.
chromatids
67
Chromatids are attached at the ____________.
centromere
68
The _____________ is a protein structure within the centromere that provides a point of attachment for microtubules during cell division
Kinetochore
69
What are rounded, dense, well-defined nuclear bodies with no surrounding membrane that number one to four per nucleus?
Nucleoli
70
Nucleolus produces what?
Ribosomal ribonucleic acid (rRNA)
71
The organelles where proteins are produced are called?
Ribosomes
72
What is the endoplasmic reticulum?
Series of membranes forming sacs and tubules that extends from the outer nuclear membrane into the cytoplasm
73
Rough ER is?
ER with ribosomes attached to it
74
ER without ribosomes is called?
The smooth ER
75
What makes up the Golgi Apparatus?
Consists of closely packed stacks of curved membrane bound sacs
76
What does the ER pinch off to form a small sac called a?
transport vesicle
77
What does a transport vesicle do?
moves to the Golgi Apparatus, fuses with it's membrane and releases protien into it's cisterna
78
What are secretory vesicles?
Small, membrane bound sacs that transport material produced in cells to the exterior of cells
79
Lysosomes are?
Membrane bond vesicles formed from the Golgi Apparatus
80
Peroxisomes are?
small membrane-bound vesicles containing enzymes that break down fatty acids, amino acids, and hydrogen peroxide
-->These cells break down hydrogen peroxide and are active in detoxification
81
What are proteasome?
Tunnel like structures, similar to channel protein and not bounded by membranes
82
What are bean-shaped, rod-shaped, or thread-like organelles with inner and outer membranes separated by a space?
Mitochondria
83
Cilia are?
cylindrical shaped microtubules that that can move and push materials along the surface of cells
84
Flagella are like cilia but...
are much longer, and they occur only one per cell
85
Microvilli are
Specialized extensions of the plasma membrane that are much shorter than cilia, supported by microfilaments but do not actually move. They increase the surface area of cells
86
Three consecutive nucleotides are called _______.
Triplets
87
The molecular definition of a _________ is all the triplets necessary to make a functional RNA or protein.
Gene
88
What modifies mRNA before it leaves the nucleus to form functional mRNA that is used to code for a protein?
Posttranscriptional processing
89
What code for part of a protein?
exons
90
What does not code for a protein?
introns
91
Introns removed from the mRNA and the exons are spliced together by by enzymes are called?
spliceosomes
92
After the initial part of mRNA is used by the ribosome, another ribosome can attach to the mRNA and begin to make a protein. The resulting structure is called what?
polyribosomes
93
What is post translational processing?
making changes to proteins after they are produced
94
Manu proteins are longer when are longer when first made then they are in their final, functional state. These are called?
Proproteins
95
What are the 4 stages of mitosis?
prophase, metaphase, anaphase, telophase
96
What is the division of the cytoplasm of the cell to produce two new cells?
cytoplasm
