Exam 1 Biology 1 UTD Flashcards
1
Q
What is the framework of most biological molecules?
A
Carbon bonded to other carbon molecules, or other types of atoms
2
Q
What are hydrocarbons and their characteristics?
A
Covalently bonded hydrogens and carbons with nonpolar properties (Bonds have considerable energy)
3
Q
What are functional groups?
A
Small, reactive groups of atoms that give larger molecules specific chemical properties
4
Q
Name the different functional groups (Covalently bonded):
A
6 groups - hydroxyl, carbonyl, carboxyl, amino, phosphate, sulfhydryl
5
Q
What is a hydroxyl group?
A
H-O, enables an alcohol to form linkage with other organic molecules through dehydration syntheses reaction
6
Q
What is a carbonyl group?
A
C=O, are major building blocks of carbohydrates & participate in rxns supplying energy for cellular activity
7
Q
What is a carbonyl group - aldehyde?
A
C=O that are @ ends of carbon & needs an H to complete
8
Q
What is a carbonyl group - ketone?
A
C=O that is in the middle of molecules
9
Q
What is a carboxyl group?
A
COOH, O=C-OH, gives organic molecules acidic properties because OH group readily releases the H+ proton, converting it from non-ionized to ionized form
10
Q
What is the amino group?
A
NH2, H-N-H, acts as an organic base by accepting H+ proton for a full octect with a (+) charge converting from non-ionized to ionized form (NH2->NH3)
11
Q
What is a phosphate group?
A
PO4, weak acids becuase the OH groups readily release their H+ protons in aqueous solutions, converting from non-ionized to ionized
12
Q
What is a sulfhydryl group
A
S-H, easily converted into a covalent linkage by losing hydrogen atoms forming a DISULFIDE LINKAGE (S-S & 2H+)
13
Q
What are isomers?
A
Molecules with the same molecular or empirical formula, but different chemical structures
14
Q
Name the different kinds of isomers:
A
structural, stereoisomers, and enantiomers (a subcategory of stereoisomers)
15
Q
What are structural isomers?
A
Same chemical formula but arrangement of atoms are different (the atom groups have moved within the molecule - different structure)
e.g. glucose - aldehyde, fructose - ketone
16
Q
What are stereoisomers?
A
differ in how groups attached (atoms groups doesn’t move in the molecule)
17
Q
What are stereoisomers - enantiomers?
A
mirror image molecules - chiral carbon (like your left and right hand: they look the same, but you can’t stack them)
Examples: L & D sugars
18
Q
What are macromolecules
A
large organic molecules - carbohydrates, lipids, proteins, nucleic acids
19
Q
What are monomers and polymers?
A
Monomers are chemically similar subunits that ultimately build polymers through dehydration synthesis
20
Q
What is dehydration synthesis?
A
Formation of large molecules by the removal of water (Monomers joined to form polymers)
21
Q
What is hydrolysis?
A
Breakdown of large molecules by the addition of water (Polymers broken down into monomers)
22
Q
What ratio is present within carbohydrates?
A
- Molecules have a 1:2:1 ration of carbon, hydrogen, and oxygen (Good energy storage molecules)
- C-H covalent bonds hold much energy
- Examples: sugars, starch(polymer), glucose(monomer)
23
Q
What is a monosaccharide
A
- Simplest carbohydrate composed of a basic six-carbon SUGAR (Enzymes that act on different sugars distinguish between isomers)
- C6H12O6 - glucose, fructose, galactose
- is a monomer
24
Q
What is a structural isomer of glucose (aldehyde) C6H12O6?
A
Fructose (ketone)
25
What is a stereoisomer of glucose C6H12O6?
Galactose
26
What is the difference between alpha-glucose and beta-glucose?
There is carbon-one with hydroxyl group facing down (Alpha-glucose), or facing upwards (Beta-glucose)
27
What is the linear form of glucose?
Simple carbohydrate (C6H12O6) with carbonyl group (C=O) @ carbone-one & hydroxyl group (H-O) @ carbon-5
28
What are disaccharides?
1. Two monosaccharides linked by dehydration synthesis (Used for sugar transport and energy storage)
2. Is a polymer
3. Examples: sucrose, lactose, maltose
29
Name the different disaccharide linkages and molecules:
a.) Maltose: two alpha-glucose molecules (Alpha 1->4 linkage)
b.) Sucrose: glucose and fructose molecules (Alpha 1->2 linkage)
c.) Lactose: glucose and galactose molecules (Beta 1->4 linkage)
30
What are polysaccharides?
1. Long chains of monosaccharides linked through dehydration synthesis (Linear, or branched molecules)
2. Energy storage (plants use starch [amylose], animals use glycogen)
3. Structural support (plants use cellulose, anthropods and fungi use chitin)
31
Name the different polysaccharides:
Amylose (starch), glycogen, cellulose, chitin
32
What are the linkages and function of the polysaccharide amylose?
1. A plant starch
2. Energy storage
3. Formed with α-glucose joined in chains (end to end) by alpha(1->4) linkages
33
What are the linkages and function of the polysaccharide glycogen?
1. Found in animal tissues
2. Energy storage
3. Formed with α-glucose joined in chains & branches by alpha(1->4) and alpha(1->6) linkages
34
What are the linkages and function of the polysaccharide cellulose?
1. Primary fiber in plant cell walls
2. Structural support
2. Formed with β-glucose joined in chains by beta(1->4) linkages
35
What are the linkages and function of the polysaccharide chitin?
1. fiber win external skeleton of anthropods (insects) and fungi cell walls
2. Structural support
3. Formed from derivitives of glucose joined in chains by beta(1->4) linkages
36
What are the monomers of nucleic acids (DNA and RNA)?
1. Nucleotides (Composed of sugar + phosphate + nitrogenous base)
2. Connect nucleotides by phophodiester bonds
3. Sugar is deoxyribose (D) in DNA or ribose (R) in RNA
37
From smallest to largest, how are nuleosides, nucleotides, and nucleic acids put in order?
Nucleosides (are in ->) nucleotides -> nucleic acids (DNA or RNA)
38
What bonds connect nucleotides?
Phophodiester bonds
39
What are nucleic acids?
Polymers made from Nucleotides (2 types = DNA and RNA)
40
What is a nucleoside?
A nitrogenous base + five-carbon sugar (Lacks the phosphate group)
41
Name the types of nitrogenous bases:
Pyrimidines: one carbon-nitrogen ring (Uracil or thymine, cytosine)
Purines: two carbon-nitrogen rings (Adenine, guanine)
42
What is the main difference between ribonucleotides and deoxyribonucleotides?
In the sugar, there is either hydrogen at carbon-2 (Deoxyribose) or a hydroxyl (OH) group (Ribose)
43
What is a phosphodiester bond?
Forms between the 5' carbon (Phosphate group) of one nucleotide and the 3' carbon (Sugar) of another
44
What does Uracil (U) look like?
A pyrimidine; 6 ring, no methyl group
45
What does thymine (T) look like?
A pyrimidine; 6 ring with methyl group on C2
46
What does cytosine (C) look like?
A pyrimidine, 6 ring with NH2 on C1 (instead of a ketone)
47
What does adenine (A) look like?
A purine, 6 ring connected to a 5 ring, NH2 on C1
48
What does guanine (G) look like?
A purine, 6 ring connected to 5 ring, ketone on C1 and amid on C5
49
What are ring-shaped sugars?
1. 5-carbon deoxyribose in DNA or ribose in RNA
2. The 2 sugars differ only in the atom group @ the 2' carbon with hydrogen (H) in deoxyribose or hydroxyl (OH) in ribose
3. In unlinked, the 5' carbon can have 1-3 phosphate groups connected by phosphodiester bonds
50
Describe the function and structure of DNA:
1. Encodes information for amino acid sequences of proteins
2. Contains double helix (2 polynucleotide strands connected by hydrogen bonds)
3. Sequences of bases (A//T or U, C///G)
4. Backbone are held together by phohodiester bonds which link sugar to phosphate & at center are nitrogenous bases (A,G,U orT,C) bonded by a hydrogen
51
What is the difference in hydrogen bonds for the different complimentary base pairs?
Adenine and thymine have only 2 hydrogen bonds; guanine and cytosine have 3 hydrogen bonds
52
What is complementary base pairing?
Pairing of A—T or G—C to determine sequence of DNA (DNA replication uses these rules as a template)
53
Describe the structure and function of RNA:
1. Single polynucleotide strand
2. Uses information from DNA to sequence amino acids in proteins in ribosomes (DNA is like the headquarter and RNA are like the managers)
3. Contains ribose
54
What are some other nucleotides?
a.) ATP: primary energy currency of the cell
b.) NAD+ and FAD+: electron carriers for many cellular reactions
55
What is ATP?
1. Adenosine Triphosphate - ENERGY - is required for active transport
2. Has an adenine nitrogenous base
3. Has a ribo sugar
4. Has the phosphate groups
56
What are some functions of proteins?
1. Defense
2. Enzyme catalysis
3. Motion
4. Regulation
5. Support
6. Storage
7. Transport
57
What is the structure of proteins?
1. Polymers composed of amino acids (Monomers) synthesized by dehydration synthesis to form chains of polypeptides connected by peptide bonds
2. Unbranched
58
What is the basic structure of an amino acid?
Central C, amino group (NH2), carboxyl group (COOH), single H, and variable R group
59
What are the animo acid 4 classes?
1. Nonpolar (hydrophobic)
2. Polar uncharged (hydrophilic)
3. Negatively charged
4. Positively charged
60
What are the nonpolar amino acids?
Glycine (Gly, G), Alanine (Ala, A), Valine (Val, V), Leucine (Leu, L), Isoleucine (Ile, I), Phenylalanine (Phe, F), Tryptophan (Trp, W), Methionine (Met, M), Proline (Pro, P)
Hydrophobic
61
What are the uncharged polar amino acids?
Cystein (Cys, C), serine (Ser, S), threonine (Thr, T), tyrosine (Tyr, Y), asparagine (Asn, N), glutamine (Gln, Q)
Hydrophilic
62
What are negatively charged amino acids?
Aspartic acid (Asp, D), glutamic acid (Glu, E)
Hydrophilic
63
What are positively charged amino acids?
Lysine (Lys, K), arginine (Arg, R), histidine (His, H)
64
What are the amino acid structures that we need to draw?
Glycine (Gly, G), Serine (Ser, S), Threonine (Thr, T), Aspartic Acid (Asp, D), Tyrosine (Tyr, R), Phenylalanine (Phe, F), Isoleucine (Ile, I), Cysteine (Cys, C)
65
What is a disulfide linkage (S-S)?
Linkage between the sulfhydryl groups (S-H) of two cysteine amino acids after oxidation (removal of electron)
66
What is a peptide bond?
1. Link amino acids into polypeptide bonds (the subunits of proteins)
2. Formed by dehydration synthesis between amino group (NH2) and carboxyl group (COOH) between 2 different amino acids
3. Water is a by-product
4. Has an N-terminal and C-terminal end
5. New amino acids are linked to the C-terminal end
67
What has 4 levels of structure?
Proteins
68
Name the different structures of proteins:
a.) Primary structure: sequence of amino acids (Determines the function of a protein)
b.) Secondary structure: alpha-helices and beta-sheets stabilized by hydrogen bonds
c.) Tertiary structure: (3D dimension) determined by disulfide linkages and hydrogen bonds (Function/solubility)
d.) Quaternary structure: arrangement of subunits into a protein with multiple polypeptide chains
Primary Structure (are in ->) Secondary structure -> tertiary structure -> Quaternary structure
69
What is the primary structure of a protein?
Sequence of amino acids
70
What is the secondary structure of a protein?
Interaction of groups in the peptide bond by hydrogen bonds
1) Twisting of the alpha helix
2) Beta sheets
3) random coil
- irregularly folded that act as "hinges" for alpha helic and beta sheets
71
What is the tertiary structure of proteins?
1. Gives protein its overall 3D shape (conformation)
2. Determined by primary structure
3. Determines protein function from side groups
72
What is the quaternary structure of a protein?
Arrangement of individual chains (subunites) in a protein with 2+ polypeptide chains
73
What affects the conformation of a protein?
Disulfide linkages, interaction of polar and nonpolar groups, and hydrogen bonds
74
What are motifs?
Common elements of secondary structure capable of determining structure of unknown proteins
75
What is the difference between the N-terminal and C-terminal?
N-terminal is the end of an amino acid (No linkage) and c-terminal allows for linkage of new amino acids
76
What are domains?
1. Functional units within the large structure of a polypeptide (Have many different functions)
2. Most proteins made of multiple domains that perform different parts of the protein's function
77
How many domains does an enxyme that assembles DNA have?
It has 2. Domain a creates DNA (polymerase site) and domain b corrects accidental DNA creation (exonuclease site)
78
Name some different protein combinations:
a.) Lipoproteins: proteins + lipids (Form cell membranes)
b.) Glycoproteins: carbohydrates + proteins (Enzymes, antibodies, recognition and receptor molecules, and parts of extracellular supports)
c.) Nucleoproteins: nucleic acids + proteins (Form chromosomes - genetic info)
79
What are chaperones?
Proteins that help a protein fold correctly (Cystic fibrosis is an example of a deficiency)
80
How do chaperonin (a class of chaperones) fold proteins?
Unfolded polypeptide enters, and is enclosed by a cap (Folding occurs, and the cap is released)
81
What is denaturation?
Protein loss of structure and function because of environmental conditions (Temperature, pH, ionic concentration of solution)
- Ion: atom/molecule with net charge
82
What is the significance of Anfinsen's experiment?
After renaturization, showed that the conformation of protein is found within the amino acid sequence (Ribonuclease - primary structure)
83
What are lipids?
Group of molecules that are insoluble in water (hydrophobic) because of high proportion of nonpolar bonds (C—H)
84
What are some different kinds of lipids?
Trigylceride(Neutral lipids or Fatty AcidS): energy storage molecules (Nonpolar)
- Oils: liquid at biological temperatures
- Fats: semisolid [ ONe Fatty acid: contain a single hydrocarbon chain (can be however long) with a carboxyl group (COOH)]
85
What are triglycerides?
Formed by dehydration synthesis to make a covalent bpnd (ester linkage) between a three-carbon glycerol & three fatty acid chains (nonpolar)
86
What is an ester linkage?
A covalent bond (ester linkage) between the carboxyl group (COOH) of the fatty acid and hydroxyl group (OH) of the glycerol in a triglyceride
87
Name the two kinds of fatty acids:
a.) Saturated fatty acids: found in solid animal fats (Contain only single C—C bonds)
b.) Unsaturated fatty acids: found in vegetable oils (Contain double C=C bonds that bend)
- unsaturated so missing H atoms
- considered healthier than saturated in human diet
88
What is hydrogenation?
Plant oils being converted into saturated fats (Unsaturated fatty acids are much healthier)
- add H atoms
89
What is atherosclerosis?
Build up of plaques within the coronary arteries (Caused by the excess buildup of cholesterol [a type of lipid])
90
What are phospholipids?
Composed of glycerol (Polyalcohol), two fatty acids (Nonpolar tails [hydrophobic]), and a phosphate group (Polar [hydrophilic])
- form ALL biological membranes
- HAS a polar unit to make up a type
91
What are the four different types?
a.) Phosphatidyl serene
b.) Phosphatidyl choline
c.) Phosphatidyl inositol
d.) Phosphatidyl ethanolamine
ALL found in biological membranes
92
What is a micelle?
Lipid molecules that orient with hydrophilic end towards water, and hydrophobic end away from water
93
How is the phospholipid bilayer constructed?
1. More complicated structure than micelle where 2 layers form
2. One end is exposed to the aqueous environment (Phosphate group - Polar/hydrophilic) and the other is contained inside (Hydrocarbon - Nonpolar/hydrophobic)
3. Film of phospolipids 2 molecules thick
94
What are cell characterisitics?
(Like common basic structures)
1. Genetic material (DNA)
- single circular molecule in prokaryotes
- double helix in nucleus in eukaryotes
2. Cytoplasm: fills cell interior
3. Plasma membrane: encloses the cell
Extra - 4. Ribosomes: synthesize proteins
95
What is the difference between genetic material in prokaryotes and eukaryotes?
Is a singular circular molecule called the nucleoid (Prokaryotes) vs. A double helix in the nucleus (Eukaryotes)
96
Who discovered cells?
Robert Hooke in 1665
97
Who proposed cell theory?
Schleiden and Schwann
98
What are the tenants of cell theory?
1. All organisms are composed of cells
2. Cells are the smallest living unit of all living organisms
3. Cell arise by division from preexisting cells
99
What is the cell size limited by?
Surface area to volume ratio
100
What does the cell surface area determine?
The rate at which nutrients diffuse across the membrane into a cell and the rate at which waste products diffuse out (the amounts of substances that can be exchanged)
101
What happens when you double the diameter of a cell (most are <50 micrometer)?
SA increases 4x and volume increases 8x (Cell size is limited because of a surface area-to-volume ratio)
102
How do cells increase surface area?
With the usage of extensions or folds (Allows for greater diffusion and movement of cargo)
103
What is resolution?
Minimum distance two points can be apart to be distinguished as separate (100 micrometers for human eye)
104
8.) Name the types of microscopes:
Light microscopes: use lens with visible light
- 200 nanometers apart
- limited
Electron microscopes: uses beams of electrons
- Resolve structures down to 0.2 nanometers apart
105
Common references for units of measure
electron microscope [hydrogen atom = 0.1 nm]
(sees more than >)
light microscope [large organelles and cells - micro and milli]
>
human eye [chicken egg=3cm]
106
What are the Basic Structural Similarities between prokaryotes and eukaryotes?
1. DNA (genetic material) @ nucleoid (prokaryotes) or nucleus (eukaryotes)
2. Cytoplasm: semifluid containing organelles and cytosol (the fluid)
3. Ribosomes: synthesize proteins
4. Plasma membrane: phospholipid bilayer
107
Name some characteristics of prokaryotic cells:
Simplest organisms (DNA present in nuceloid - Lack a membrane-bound nucleus)
Cell wall outside the plasma membrane (contain ribosomes - not membrane bound organelles)
- lack interior membranes (endomembrane system) for organelles (no compartments)
Two domains: archaea and bacteria
108
What is the function of the bacterial cell wall?
1. composed of peptidoglycan
2. Protects the cell, maintains shape, and prevents excessive uptake or loss of water
3. Susceptibility of bacteria to antibiotics depends on cell wall structure
- ARCHAEA lack peptidoglycan (weaker and only found in gut)
- bacteria more common found in organs
109
How to antibiotics work?
Target weaknesses within the cell wall of bacterium (Archaea lack peptidoglycan)
Prevents bacteria from creating more peptidoglycan (which provides wall with strength to survive in human body)
110
What is a eukaryotic cell?
Characterized by:
a.) Compartmentalization by endomembrane system: a group of membranes and organelles that works together to modify, package, and transport lipids and proteins
b.) The presence of membrane-bound organelles
c.) plant cell and animal cell
d.) posess a cytoskeleton (network of protein filaments and tubules in the cytoplasm)
111
What are the differences in organelles between plant and animal cells?
Plants cells
- have chloroplasts
- have cell wall outside of cell membrane
- usuallu only ONE large & centered vacoules
Animal cells
- multiple smaller & at periphery vacoules
112
What are some of the organelles in cells?
a.) Nucleus - inheritance, RNA production
b.) Mitochondria - ATP (energy) production
c.) Golgi (mail man)- glycosylation (tells protein where to go) & secretion (packaged into discrete transport packets or vesicles and discharged)
d.) Lysosomes - degradation through autophagy (@ oxygen poor areas)
e.) Peroxisomes - degradation, detoxification (@oxygen rich areas)
113
What is the function of the single nucleus organelle?
Holds genetic information (DNA)
@ Nucleolus - makes ribosomes through the production of ribosomal RNA (rRNA) + ribosomal subunits
114
Define the parts of the nuclear envelope:
2 phospholipid bilayers (Reinforced by protein filaments called lamins)
- cell membrane only has ONE
Nuclear pore: regulates passage of molecules in and out
115
How is DNA organized in eukaryotes?
It's divided into multiple linear chromosomes (Chromatin is DNA and protein - around nucleolus)
116
What is the nucleoplasm?
The liquid within the nucleus (Comparable to the cytoplasm within the plasma membrane)
117
Breakdown the different parts of cell fractionation (research method):
Whole cells
->
Cell fragments
->
500 g [g = force of gravity] - leaves nuclei
->
20,000 g (Mitochondria or chloroplasts)
->
150,000 g (Ribosomes, proteins, nucleic acids)
118
Name some different characteristics of Eukaryotic Ribosomes:
Composed of a large and small subunit (Formed in nucleolus)
Freely suspended in cytosol or attached to membrane-bound (Rough ER)
Site of protein synthesis (Arrange amino acids into primary structure)
- Proteins on FREE ribosomes may remain in cytosol, enter nucleus, or become parts of other structures
- Proteins attached to Rough ER follow a special path
119
What are ribosomes made up of?
rRNA (2 subunits) and proteins
120
What is the endomembrane system?
A series of cytoplasmic membranes throughout cytoplasm that divides the cell into sections with different functions
- nuclear envelope
- ER
- golgi
- lysosomes
- vesicles (can transport and store substances within a cell from one cell to another)
- plasma membrane (cell membrane)
121
What is the endoplasmic reticulum (ER)?
Reticulum (= network) of membranous channels & cisternae (= single membrane) that enclose spaces (= lumen)
Occurs in 2 forms: Rough & smooth
122
What is the function of rough ER?
At lumen, folds proteins from ribosomes into final form & makes chemical modifications before packaging into vesicles
Proteins delivered to golgi complex within small vesicles that pinch off from ER
123
What is the function of smooth ER?
Synthesizes lipids that become a part of cell membranes
In liver, smooth ER convert toxins into tolerable substances
124
What is the Golgi apparatus?
Reticulum (network) of Golgi bodies (flattened sacs with interconnected membranes)
Has cis (in), medial, & trans (out) compartments
- Collects (stores secreted materials), packages, and distribute molecules (using vesicles)
- sugar production and addition to proteins & lipids to form glyoproteins
- final protein folding
125
Describe the process of Golgi complex function:
a.) Proteins from the rough ER enter on the cis face (Delivered by transport vesicles)
b.) Modified proteins exit on the trans face (Transported in secretory vesicles)
c.) Exocytosis: membrane of secretory vesicle fuses with membrane and releases contents extracellularly (out from cell)
126
What is endocytosis?
Plasma membrane (cell membrane) forms endocytic vesicles and pinches off into the cytoplasm
127
Where to endocytic vesicles travel?
Golgi complex or lysosomes
128
Describe lysosome structure and function:
a.) Membrane-bound digestive vesicles with an acidic pH ~ 5
b.) Come from the Golgi apparatus
c.) Destroys cells and foreign material by autophagypinocytosis (soluble)
- phagocytosis (insoluble)
d.) Enzymes (catalysts) catalyze the breakdown of macromolecules
129
What are the different kinds of lysosomal processes?
Autophagy (Self-destruction), phagocytosis (Insoluble material), and pinocytosis (Soluble material)
130
What are peroxisomes?
Vesicles that contain enzymes involved with oxidation of fatty acids (harmless Hydrogen peroxide by-product)
131
Name the steps in the secretory pathway:
a.) Proteins made by Rough ER ribosomes or lipids by Smooth ER enter lumenal space and undergo modification
b.) Transport vesicles bud off from the ER membrane and transport cargo to the Golgi complex
c.) Protein and lipid modification completed in the Golgi complex (Packaged in secretory vesicles)
d.) Vesicles fuse with the plasma membrane and are released by exocytosis
e.) Endocytic vesicles encounter lysosomes and are enzymatically degraded (Form at membrane) or go back to Golgi
132
What are the 2 organelles with their own DNA?
Mitochondria and chloroplasts (only in plant cell)
- both have 2 membranes
133
Describe the mitochondria:
a.) bounded by 2 membranes
b.) cristae folds in the inner membrane
c.) Powerhouse of the cell that produces ATP through oxidative phosphorylation (Maternally inherited)
d.) several thousand per cell
e.) circular DNA (like prokaryotes)
134
What are chloroplasts?
a.) bounded by 2 membranes
b.) contain chlorophyll for photosynthesis
c.) membranous stacks of thylakoids (called grana)
- like cristae in mitochondria
135
Name some important functions of central vacuoles:
a.) Tonoplast membrane: contains transport proteins & surrounds the vacuole and regulates its overall pressure
b.) Store sugars, salts, pigments, waste products, proteins, and much more
c.) Contains molecules that provide chemical defenses against pathogens
d.) Contains enzymes that break down molecules
e.) Produce colors of flowers via pigments
136
What is the cytoskeleton?
Fibers & Filamentous structure (actin filaments, microtubule, intermediate filiaments) that is extremely dynamic
- Maintains cell shape
- transports cargo
- connects cells
- provide cell motility (movement within cell)
- move chromosomes
- compose cila
137
What is the function of actin filaments?
Involved with muscle contraction, crawling, or pinching (About 7 nanometers in diameter)
138
Describe intermediate filaments:
Mechanical strength of the cell (Tissue specific and provides structural support, 8-10 nm diameter)
139
Describe microtubules (there are many!):
a.) alpha and beta tibulin
b.) organization of cytoplasm and movement of vesicles with tracks
c.) wall consists of 13 protein filaments (linear polymers of tubulin dimers)
- dimers are head-to-tail giving microtubiles a polarity (+ and - ends)
d.) dynamic structure that can change lengths by + or - of tubulin dimers
e.) microtubules that radiate outward from cell center (centrisome) anchor organelles
- at midpoint of centrisome are 2 short, barrel-shaped structures called centrioles
f.) separate and move chromosomes during cell division
g.) move SOME eukaryotic cells themselves
140
Where do microtubules originate from?
Radiate outward from the centrosome (anchor many organelles in their positions)
141
How do microtubules transport vesicles?
How do microtubules transport vesicles?
Utilize ATP hydrolysis to m
142
Describe microtubule role in cell division:
Separate and move chromosomes, or completely move the eukaryotic cells themselves
143
What are intermediate filaments?
a.) assembled from a large varied group of intermediate filament proteins
b.) size between microtubules and microfilaments
c.) can occur singly or in network with microtubules and/or microfilaments
144
What are centrosomes?
Region surrounding centrioles in animal cells (plants and fungi lack centrioles)
Microtubule-organizing cell center - can nucleate assembly of microtubules
Microtubules -> centrioles -> centrisomes
145
What is cell movement?
Cell motion tied to movement of actin filaments (microfilaments), microtubules, or both
Actin microfilaments (to crawl) or Flagella or cilia
146
What is the arrangement of microtubules in flagella?
Have a 9 + 2 arrangement that moves in an s-wave motion (Not related to prokaryotic flagella)
147
What is the arrangement of microtubules in cilia?
Have a 9 + 2 arrangement that moves in an oar-like motion
Cilia are shorter and numerous than flagella
148
Where do flagella and cilia come from?
Arise from the centrioles (at the midpoint of centrosomes)
The centriol remains as the basal body within the innermost END of the structure (like a base)
149
