Cell- Chapter 3B Flashcards
(115 cards)
0
Q
What is the perinuclear space
A
Space between the double membrane of the nuclear envelope
1
Q
What is the function of the nuclear envelope
A
Composed of a double membrane. Separates nucleus from cytoplasm
2
Q
What’s the function of the nuclear pores
A
Allows chemical communication between nucleus and cytoplasm
3
Q
What is the fluid contents of nucleus
A
Nucleoplasm
4
Q
What’s the function of the nucleoli
A
Transient nuclear organelles.
Assemble RNA subunits.
Manufacture large amounts of proteins
5
Q
What stores instructions for protein synthesis
A
DNA in the nucleus
6
Q
What forms a nucleosome
A
DNA wrapped around histone molecules
7
Q
What is the difference between chromatin and chromosomes
A
Chromatin loosely coiled DNA in nondividing cells
Chromosomes are tightly coiled DNA in dividing cells
8
Q
What are the two copies of each chromosome held together by
A
Centromere
9
Q
What is a somatic cell
A
General cell that makes up the body
10
Q
How many chromosomes does each cell have
A
46
23 pairs
11
Q
What are the four nitrogenous bases of DNA
A
- Adenine
- thymine
- Cytosine
- Guanine
12
Q
The genetic code is known as
A
Sequences of nitrogen base pairs
13
Q
What is the triplet code
A
Sequence of 3 nitrogen bases
Signifies a single amino acid
14
Q
What is a gene
A
The functional unit of heredity
15
Q
What contains all the DNA nucleotides to produce a specific protein
A
A gene
16
Q
What are the 7 steps in protein synthesis
A
- Gene activation. Remove histones, DNA uncoils
- DNA strand separates
- Nucleotides into single strand of mRNA
- mRNA leaves nucleus through nuclear pores
- Codons of mRNA bind to anticodons on tRNA.
- tRNA carries specific amino acid
- rRNA of ribosome strings amino acids together
17
Q
What is a series of three RNA nucleotides called
A
Codon
18
Q
What is transcription and where does it take place
A
Takes place in the nucleus and is the production of RNA from DNA template.
19
Q
What are the steps of transcription
A
- Gene activation at control segment (promoter)
- Begin assembly of mRNA strand. RNA polymerase binds to promoter.
- Continuation of mRNA strand. Polymerase promotes hydrogen bonding between DNA template and complementary RNA nucleotides
- Transcription ends. Stop codon reached. mRNA detaches. DNA strands reassociate
20
Q
The initial strand of mRNA is called ____________
A
Immature mRNA
21
Q
What additional processing does mRNA require before leaving the nucleus
A
Introns are removed and remaining exons are spliced together
22
Q
What are introns
A
Non coding sequences involved with mRNA
23
Q
What are exons.
A
The required coding segments that are spliced together to form shorter more functional mRNA
24
What is translation
Formation of a chain of amino acids from an mRNA strand
25
What changes genetic information from nucleic acids to proteins
Translation
26
Where does translation occur
The cytoplasm on ribosomes
27
What are the three phases of translation
1. Initiation
2. Elongation
3. Termination
28
How long does translation process take to produce a protein
~20 seconds
29
True or false multiple ribosomes cannot attach to a single protein
False they can to quickly produce more proteins
30
Describe the 3 sorts of permeability
1. Freely permeable- any substance can pass through
2. Selectively Permeable- some can pass
3. Impermeable- no substance can pass
31
What is the only permeability in living cells and why
Selectively permeable in order to enable intercellular communication
32
What is the difference between active and passive transport and give an example of each
Passive does not require ATP (diffusion)
Active does require ATP (vesicular transport)
Carrier mediated transport can be both passive and active
33
What is diffusion
Random movement of ions or molecules in a liquid or gas resulting in even distribution
34
What is a concentration gradient
Concentration difference when molecules are not evenly distributed
35
What are 4 factors that influence diffusion
1. Distance
2. Temperature
3. Electrical forces
4. Concentration gradient
36
What is osmosis
Net diffusion of water across a membrane
37
What is the movement of water driven by osmosis
Osmotic flow
38
What is osmotic pressure
Force of pure water moving into a solution with higher solute concentration
39
What is hydrostatic pressure
Fluid force
40
What is osmolarity
Total solute concentration in an aqueous solution
41
What is tonicity
How a solution affects a cell
42
What are the three effects of tonicity
1. Isotonic
2. Hypotonic
3. Hypertonic
43
What is an isotonic solution
Solution that does not cause osmotic flow across membrane
44
What is a hypotonic solution
Causes osmotic flow into cell
45
What is a hypertonic solution
Cause osmotic flow out of cell
46
What happens to a red blood cell with a hypotonic tonicity
Process called hemolysis. Cell will swell and burst
47
What happens to a RBC with a hypertonic tonicity
Process called crenation. Cell will shrivel and die
48
What will happen if a patient is administered a solution that has the same osmolarity as their interstitial cellular fluid but higher concentration of individual ions.
1. Diffusion of solutes may occur across cell membrane.
| 2. Cell volume increases
49
What is the contents of normal saline and what tonicity does it have with blood in the body
Saline is a liquid composed of 0.9% NaCl it is isotonic with blood
50
What are carrier proteins
Proteins that transfer hydrophilic or large molecules across cell membrane
51
Explain the cotransport process
Carrier proteins that move more than one substance in the same direction
52
What is the process called where proteins carry more than one substance in opposite directions across the cell membrane
Process is called countertransport
53
What is the carrier involved with countertransport called
An exchange pump
54
What are the 3 types of carrier mediated transportation
1. Facilitated diffusion
2. Active transport
3. Secondary active transport
55
What is facilitated diffusion
Requires no ATP. Carrier binds to molecule and changes shape. Moves from area of high concentration to area of low concentration across membrane.
56
What is active transport.
Active process that requires ATP. Independent of concentration gradient
57
What process may use up to 40% of ATP in resting cell
Sodium potassium pump. The process exchanges 3 intracellular sodium ions for 2 extra cellular potassium ions
58
How does the secondary active transport method work
Transport process itself does not require ATP
Cell often needs ATP to maintain homeostasis
Moves one or more substances following the concentration gradient
59
What is vesicular transportation
Materials move across cell membrane in small membranous sacs called vesicles
60
Does vesicular transportation require ATP
YES
61
What is endocytosis
Importing extracellular substances into vesicles
62
What is an endosome
The vesicles that import extracellular substances
63
What is Exocytosis
Movement of waste from intracellular vesicle to outside the cell
64
What are the three types of endocytosis
1. Receptor mediated endocytosis
2. Pinocytosis
3. Phagocytosis
65
What is receptor mediated endocytosis
Brings in specific molecules into cell using receptors on membrane surface
66
What are the steps involved with receptor mediated endocytosis
1. ligand binds to receptor
2. membrane folds around receptors forming pocket that pinches off
3. Endosome called coated vesicle form
4. Vesicle fuses with lysosome
5. Ligand free from receptor and enter cytosol
6. Lysosome detaches from vesicle
7. Vesicle fuses with membrane again
67
What process is referred to as cell drinking
Pinocytosis
68
What is pinocytosis
The formation of endosomes with extracellular fluid that brings in fluid and small molecules
69
What process is referred to as cell eating
Phagocytosis
70
What is phagocytosis
Cytoplasmic extensions surround very large object and bring it into the cell
71
What kind of cells can perform phagocytosis
1. Phagocytes
| 2. Macrophages
72
What is a pseudopodia
false foot; cytoplasmic extensions that surround an object
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What is a phagosome
May be as large as the cell contains the solid object
74
How many cells are in the body
75 trillion
75
What is responsible for the initial increase in cell number
Cell division
76
What is apoptosis
Genetically controlled cellular death
77
What are the 2 types of cell division
1. Mitosis
| 2. Meiosis
78
What is the differences between mitosis and meiosis
Mitosis produces 2 daughter cells each containing 46 chromosomes
Meiosis produces sex cells each containing 23 chromosomes
79
What is interphase
Non dividing period where cells perform normal activities
80
What are the 4 steps of interphase
1. G0
2. G1
3. S
4. G2
81
What are somatic cells
Body cells
82
What is G0 and give an example of a cell that stays in this phase
Cells not preparing to divide and performing normal cellular functions.
EX Skeletal muscle cells
83
What cells NEVER enter G0 and divide repeatedly
Stem cells
84
What is G1 phase
Normal cell functions, duplication of organelles, protein synthesis
85
What is S phase
DNA replication
86
What G2 Phase
Last minute protein synthesis and centriole replication
87
What are the steps in the DNA replication process
1. DNA helicase
| 2. DNA polymerase
88
What is DNA helicase
Unwinds DNA strands. Disrupts hydrogen bonds
89
What is involved with DNA polymerase
1. binds to exposed bases
2. promotes bonding between DNA strand and complementary nucleotides
3. one polymerase works continuously alone one strand of 'zipper'
4. two new DNA segments spliced together with DNA ligases
5. 2 identical DNA strands formed
90
What is m phase of a cell
Process that include mitosis and cytokinesis
91
What are the 4 steps involved with mitosis
1. Prophase
2. Metaphase
3. Anaphase
4. Telophase
92
What is mitosis
Division and duplication of the cells nucleus
93
What is cytokinesis
Division of cells cytoplasm
94
Explain prophase
Nuclear envelope disintegrates
| Chromosome coil and become visible
95
What is the name for each copy of chromosomes
Chromatid
96
What is a kinetochore
Raised region where centromere attaches
97
What extends from the centrioles
Astral Rays
98
What interconnects centriole pairs
Spindle fibers
99
Explain metaphase
Chromosomes align at metaphase plate
100
Explain anaphase
Centromere splits
| Chromatids are drawn toward opposite sides along spindle apparatus
101
Explain telophase
Cell is preparing to enter interphase
Membranes reform
Cytoplasm constricts
102
What is a cleavage furrow
The area where cytoplasm constricts along the metaphase plate
103
How does the cytokinesis begin
The formation of a cleavage furrow
104
The completion of cytokinesis marks__________
The end of cell division
105
What is cancer
Illness that disrupts normal rates of cell division
106
What is a mutation
Permanent DNA sequence changes
107
Where is cancer most common
Tissues with actively dividing cells
108
What is a neoplasm
Tumor
109
What is a tumor
Mass or swelling produced by abnormal cell growth
110
What kind of tumor remain within the original tissue and is seldom a threat
Benign tumor
111
What is a malignant tumor
Cells divide rapidly and are a threat
112
What is angiogenesis
Chemicals released that stimulate blood vessel growth to tumor area
113
What is it called when tumor spreads
Invasion
114
What is it called when the tumor migrates to other areas and establishes a new tumor
Metastasis
