Bio Test #6 Flashcards
(166 cards)
1
Q
Where do eukaryotic cells occur?
A
Eukaryotic cells occur in algae, protozoa, fungi, plants, & animals
2
Q
What are characteristics of Eukaryotic cells?
A
Euk. cells can be unicellular or multicellular, from 5 micrometers to 100 micrometers
3
Q
How are eukaryotic cells characterized?
A
They are characterized by nucleus & organelles
4
Q
What are the 2 types of Endoplasmic Reticulum?
A
Smooth ER & Rough ER
5
Q
What is the structure of smooth ER?
A
has a network of tubules & vesicles around the nucleus (sometimes continuous with the nucleus); membrane bound organelle
6
Q
What are functions of Smooth ER?
A
synthesis of lipids, breaks down carbohydrate, detoxify from drugs, regulates calcium concentration in the cell, produces sex hormones
7
Q
What is the structure of Rough ER?
A
has a network of tubules & vesicles (sometimes continuous with nuclear membrane); membrane bound organelle; studded with ribosomes (gibing it a rough appearance)
8
Q
What are the functions of Rough ER?
A
synthesis of protein that are needed on the cell membrane of the cell; rough ER surrounds protein with a vesicle
9
Q
What is the structure of Golgi Apparatus?
A
series of membrane bound stacks called cisterna(ae)
10
Q
What are the functions of Golgi Apparatus?
A
works with ER to repackage & transform proteins or lipids & send them to the right destination; vesicles from ER fuse with cisternae, each region of the Golgi contains enzymes that modify the content of the vesicle
11
Q
What is the structure of mitochondrian?
A
double membrane organelle; inner membrane folds & increases its surface and forming crista/ae; fluid inside is called matrix & contains ribosomes and genetic material & enzymes
12
Q
What is the function of mitochondria?
A
production of ATP
13
Q
What is the structure of lysosomes?
A
membrane bound organelle made by Golgi; it contains digestive enzymes
14
Q
What is the function of Lysosomes?
A
digest worn out organelles, food, engulfed bacteria or viruses
15
Q
What is the structure of ribosomes?
A
non-membrane bound organelles; made of rRNA & proteins & consist of 2 subunits
16
Q
What is the function of ribosomes?
A
protein production (protein that remain in the cell)
17
Q
What is the structure of centroiles?
A
barrel shaped organelle made of proteins; part of centrosome
18
Q
What is the function of centroiles?
A
involved with the organization of mitotic spindle
19
Q
What is the structure of Nuclear Envelope?
A
double membrane; has pores; impermeable to most substance
20
Q
What is the function of Nuclear Envelope?
A
protect genetic material; regulate what moves in & out of nucleus
21
Q
What is the structure of DNA?
A
deoxyribonucleic acid
22
Q
What is the structure of Chromosomes?
A
protein & DNA forms chromatin, arranged into a chromosomes
23
Q
What are the functions of DNA & Chromosomes?
A
long term storage of info, controls activity of cell, passes genetic info to daughter cell.
24
Q
What are characteristics of Mitochondrian?
A
range in size from 1 to 10 micrometers; different cells have different numbers of mitochondria
25
What is the structure of cell wall?
Its made of cellulose and has 3 layers
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Cellulose
arranged into bundles of fibers called microfibrils
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What are the functions of the cell wall?
maintains shape of cell, prevents cell from bursting, allows plant to grow against gravity
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What are the 3 layers of the cell wall?
Primary Cell wall (outside)
Middle Lamella
Secondary Cell Wall (inside)
29
What is the structure of Chloroplast?
double membrane organelle
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What is the function of chloroplast?
site of photosynthesis
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stroma
liquid inside chloroplast and contains ribosomes, enzymes, & DNA loop
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What is the structure of Central Vacuole?
liquid filled vacuole containing water, enzymes, waste, toxic substances
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What are the functions of Central Vacuole?
storage of water, support, defense
34
What are differences of animal cells compared to plants?
no cell wall, has glycogen as carb storage, roundish shape (flexible), no chloroplasts, no vacuoles or temporary vacuoles, has cholesterol in cell membrane, has centrioles
35
What are differences of plant cells compared to animals?
has cell wall, plants have starch as carb storage, rectangular shape (fixed), have chloroplast always has central vacuoles, do not have cholesterol in cell membrane, has no centrioles
36
cell membrane
a selectively permeable phospholipid bilayer found in all cells
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What is the structure of a phospholipid?
has 3 parts: phospho alcohol head, glycerol, fatty acid tail
38
Which part of phospholipid is hydrophilic?
the polar phospho alcohol head
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Which part of a phospholipid is hydrophobic?
the non-polar fatty acid tails
40
Why do phospholipids tend to arrange into a bilayer that has continuous & spherical shape?
because of the polar head & non-polar tail
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Why is the plasma membrane very flexible & can be broken with enough force?
because the tails are just close to each other but do not form bonds
42
What allows endo & exocitosis?
the plasma membrane's flexibility
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plasma membrane
semi-permeable membrane & can control what goes in & out of the cell
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Why do animal cells have cholesterol interspersed between the phospholipids?
It ensures that the membrane can function at a wider range of temperature
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Why do plant cells have a mix of saturated & unsaturated fatty acids?
to allow the membrane to function at different temperatures
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What are the types of proteins found in cell membrane?
integral, peripheral, glycoproteins
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integral
embedded in the phospholipid membrane, can have many functions (transport, enzyme, hormone binding site, cell adhesion)
48
Peripheral
adheres temporarily to the cell membrane
| can attach to integral protein
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glycoproteins
protein & carbohydrate tail
| important for cell recognition
50
What can movements of substances be?
passive and active
51
Passive
without use of energy (ATP)
52
Active
needs energy to occur (ATP)
53
What are types of Passive Transports?
Diffusion and Osmosis
54
diffusion
the passive movement of particles from an area of high concentration to an area of low concentration
55
What are types of diffusion?
simple (unaided) and facilitated
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Why does diffusion occur?
it results from the random motion of particles
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high concentration
an area with lots of molecules
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low concentration
an area with few molecules
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concentration gradient
difference between high and low
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What does it mean when molecules move along the concentration gradient?
that molecules move from an area of high concentration to an area of low concentration
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What does it mean when molecules move against the concentration gradient?
to move from low concentration to high concentration
62
What are factors that affect rate of diffusion?
concentration gradient (greater the concentration difference between 2 areas, the greater diffusion)
distance involved
area involved
barrier to diffusion
63
distance involved
diffusion over a short distance is faster then diffusion over a long distance
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area involved
the larger the area, the greater the diffusion
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barrier to diffusion
thinner the membrane the faster the diffusion
66
What are characteristics of simple diffusion?
through membrane, through channel protein, used for small uncharged molecules (cell membrane) or small & charged (channel protein)
67
Why isnt energy needed for simple diffusion?
No energy needed because molecule move WITH concentration gradient
68
What are characteristics of facilitated diffusion?
non channel protein, non channel protein binds to the substance to be moved changes shape & moves substance in, moves larger molecules
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Why isn't energy needed for facilitated diffusion?
does not need energy because substances are moved with the concentration gradient
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Why is facilitated very specific?
because each substance will need a different non-channel protein
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osmosis
passive movement of water across a semi-permeable membrane, from low solute concentration to high solution concentration
72
aquaporin
protein water moves through
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What are types of active transports?
pumps, exocytosis, endocytosis
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How do molecules move in active transports?
molecules move against the concentration gradient (from low concentration to high concentration)
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What are characteristics of pumps?
pumps are proteins embedded in the cell membrane, and specific (they can transport only certain molecules) and take the name of whatever they transport
76
What are the steps of the mechanism of pumps?
1. 3 sodium molecules bind to pump in a specific site. Binding of sodium uses ATP phosphorylation
2. phosphorylation of ATP releases energy. This energy is used to change the shape of the pump
3. Sodium can be released outside the cell & 2 potassium molecules move in to attach to a specific site different from where the sodium had attached
4. the binding of potassium to the pump causes the release of the phosphate group. This makes the pump revert to its original shape
5. potassium can be released inside the cell. Pump is ready to start again
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What are functions of membrane proteins?
Cell recognition, cell adhesion, receptors, enzyme, and transport
78
In membrane proteins, what's cell recognition?
Using glycoproteins you identify body's own cells from foreign cells
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In membrane proteins, what's cell adhesion?
Proteins bind to one another & hold cells together
| Connections are called junctions and can be temporary or permanent
80
In membrane proteins, what's receptors?
Respond to a chemical messenger & sends a signal inside the cell
81
In membrane, what's enzyme?
Breaks down a chemical messenger
| Sometimes more enzymes are grouped together to form a metabolic pathway
82
What's another name for receptors?
Hormone Binding Sites
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In membrane, what's transport?
it consists of pumps and channels
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What's a membrane protein's passive & active transport?
pumps are active transports
| channels are passive transports
85
channels
passive transport that allows water & hydrophilic molecules to move through
86
What are the 2 types of channels?
open & gated
87
What are the 3 types of gated channels?
ligand, voltage, mechanical
88
ligand
a chemical messenger opens the gate
89
voltage
a change in electric potential that opens the gate
90
mechanical
gate responds to a physical stress (pressure, stretch)
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cell cycle
describes the behavior of the cell as it grows and reproduces
92
What are the 2 phases of the cell cycle?
interphase & cell division
93
interphase
the longest phase of cell cycle & cells can be found in this phase about 80% of the time
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What are the 3 phases of interphase?
G1, S, G2
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What are the 2 phases of cell division?
mitosis and cytokinesis
96
G1 phase
cell has just finished mitosis and the cell is as small as it can be
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S phase
synthesis; DNA duplicates (chromosomes make a copy of themselves); cell continues to grow; synthesis of proteins and enzymes involved in DNA duplication
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G2 phase
final chance for cell to grow & check up to ensure cell is ready to start dividing
99
Checkpoint G1
Between G1 & S, proteins check to see if the cell is healthy & the correct size to divide. if it is, the proteins will initiate DNA duplication. If not, the cell will remain in G1 phase
100
Checkpoint G2
between G2 & Mitosis, DNA repair enzymes check to see if DNA is duplicated correctly. If it is, the protein will send signal to begin mitosis
101
Mitosis
starts with a deploid cell (2n) & produces 2 identical deploid daughter cells
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prophase
nuclear envelope begins to disappear, chromosomes condense (becoming visible), centrioles start migrating to opposite poles, spindle starts forming & attaches to the chromosomes in the centromere
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metaphase
chromosomes line up on the equator of the cell (cellplate or metaphase plate), centrioles are at opposite poles
104
What are the 4 phases of mitosis?
prophase, metaphase, anaphase, telophase
105
Anaphase
Sister chromatids are pulled apart
| Chromosomes move towards opposite poles
106
Telophase
```
Chromosomes arrive at opposite poles
Chromosomes start to elongate
Nuclear membrane reappears
Nucleolus reappears
Spindle disappears
Cell starts elongating for cytokinesis
```
107
Cytokinesis
Division of cytoplasm & organelles inside the cell
108
What's cytokinesis in animal cells?
Cell membrane starts folding in forming a cleavage furrow. Eventually the 2 sides meet up & the cell separates
109
What's cytokines In plant cells?
Golgi releases vesicles that contain cellulose
Vesicles fuse & start forming a cell plate in the middle of a cell
Cell plate grows & separate the cell
110
What are the functions of mitosis?
Tissue repair
Tissue growth
Asexual reproduction (marine invertebrate
111
hypertonic
have more solute than the solution it is compared to
112
isotonic
2 solutions will have the same concentration
113
hypotonic
solution will have less concentration of a solute than the solution it is compared to
114
tumor
when cells lose proper control of cell division and start dividing uncontrollably which forms a mass
115
What are the 2 types of tumors?
benign and malignant
116
benign
tumor that does not have the potential to spread
117
malignant
have the potential to spread
118
metastasize
when a piece can break off and move to other organs through blood system
119
What are the steps of malignant?
1. malignant tumor
| 2. angiogenesis
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angiogenesis
tumor that has recruited blood vessels to get nutrients to keep growing in size, which can form metastasis. If tumor is malignant then patient has cancelled
121
carcinogens
substances associated with an increased risk of contracting cancer
122
What gene is associated with cancer?
TP53 when turned off
123
What are factors that increase the risk of cancer?
radiations, chemicals, tobacco, stress/life, genetics, viruses
124
What causes a mutation called a thymine dimer?
UV radiators
124
What forms a kink on the DNA strand?
Two neighboring thymines on the same stand, detach from their partner and form a covalent bond between them
125
What can repair the kink in a DNA strand?
DNA repair enzymes
126
What happens to dimers that are not repaired?
It can cause cancer
127
Why don't some organisms get skin cancer?
They have DNA repair enzymes called photolyase
128
Gene therapy
Insert gene to make the enzyme in people at high risk
129
How are proteins made?
Instructions in DNA: cells make a copy of DNA (mRNA). Then it reads codons, making the protein
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mRNA
One stranded with bases of Adenine, Cytosine, Guanine, Uraci
| It is always made from matching 3' to 5' strand
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Codon
A group of 3 bases
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What does a codon correspond to?
1 amino acid
133
What reads codons in mRNA?
Ribosomes
134
How do ribosomes read codons?
They attach to mRNA and start sliding along until it finds the start codon and keeps sliding along (reading codons) until it finds a stop codon
135
What are the 3 stop codons?
UAA
UAG
UGA
136
How do we know what amino acids correspond to certain codons?
Through the genetic code table
137
What are the characteristics of the genetic code?
Universal and degenerate
138
Universal
Works in the same way in every organism
139
Degenerate
More than one codon can call in the amino acid
140
What starts every protein?
AUG starts every protein with the same amino acid methionine
141
Gene mutation
A change in the base sequence of an allele
142
What may gene mutations produce?
It may produce a different allele if the codon codes for a different amino acid
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What are different types of mutations?
A mutation can be positive, negative, or neutral
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Positive mutation
Causes an advantage
145
Negative mutation
Causes a disadvantage
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Neutral mutation
Causes now effect
147
What's the frequency if mutations have advantages to the environment?
The frequency will be higher
148
What's the frequency if mutations have disadvantages to the environment?
Frequency will be lower
149
Mutagens
Substances that cause mutations
150
How do mutations occur?
Through substitutions, insertions, and deletions
151
Substitutions
One base is replaced with another
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Insertions
One base is added
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Deletions
One base is removed
154
A mRNA strand has 27 codons. How many amino acids in this polypeptide?
26 because you don't count the stop codon
155
A gene is 6009 base pairs long. How many amino acids in the polypeptide?
After dividing by three and not counting the stop codon, there are 2002 amino acids
156
What do the codons UUA, CUA, CUG have in common?
They all have the same amino acid
157
Karyotype
Number and appearance of chromosomes of a specific organism
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How are chromosomes paired?
By size, shape, banding, & position of centromere
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When do scientists take pictures of cell for karyotyping?
In metaphase when the chromosomes are most visible
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What does each cell contain considering chromosomes?
Each chromosome is made if 2 sister chromatids.
| Each cell has to chromosomes for each pair (one father & one mother)
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Compare human sex chromosomes
In 23rd position/pair
Female are XX and the same size chromosomes
Male are XY and different size chromosomes
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What is karyotype used for?
It is used for pre-natal Diagnosis
163
Prenatal Diagnosis
Prenatal (before birth)
| Diagnosis (to identify something)
164
Aminocentesis & Chorionic Villus Sampling
Two tests used to obtain cells from fetus. Which take advantage of the fact that the placenta, amnion, & chorion are made by fetus & not mother. There fore the cells of these tissues will have the genotype of the baby
165
Amniocentesis
Removal of amniotic fluid; done at 14 weeks pregnant; fluid is extracted with syringe inserted into the abdominal wall; liquid extracted contains cells from fetus and is centrifuged, the cells are extracted and cultured. Cultured cells can be karyotyped. The liquid can be tested for neurological disorders (spina bifida)
