Chapter 3 Flashcards
(92 cards)
1
Q
Two types of cells
A
- Somatic
2. sex (sperm and oocytes)
2
Q
plasma membrane
•where is it located
•definiton
A
- outside the cell
* lipid bi layer that separates inside of the cell from surrounding extracellular fluid
3
Q
2 subdivisions of the cytoplasm
A
- cytosol (liquid component)
2. Organelles (intracellular structures)
4
Q
Nuclear envelope
•definition
•location
A
- membrane that surrounds the nucleus and separates it from the cytosol
- outside the nucleus
5
Q
Nucleolus
•location
•what is it
•function
A
- inside the nucleus
- translucent nuclear organelle
- synthesizes ribosomal RNA
6
Q
Nucleoplasm
•location
•what is it
A
- inside the cell
* fluid containing nuclear matrix
7
Q
Nuclear matrix
A
Provides support
8
Q
How is DNA organized in the nucleus
A
DNA is coiled around histone proteins to form a nucleosome
9
Q
Chromosomes
•formula
•structure of non dividing
•structure of dividing
A
- DNA + proteins = chromosomes
- loose coils (chromatin)
- tight coils (ind. chromosomes can be seen under the microscope)
10
Q
Mitotic phase (M) •2 types
A
- Mitosis
2. cytokinesis
11
Q
Mitosis
•definition
•where does it occur
•what about the DNA
A
- division of nucleus
- occurs in somatic cells
- duplicated DNA is distributed equally between 2 daughter cels
12
Q
Cytokinesis
A
Division of cytoplasm to form 2 separate cells
13
Q
Interphase
•definition
•3 phases
•what does it determine
A
• where cell spends most of its time carrying out normal functions;when ready to divide it enters G1
1. Gap1
2. Synthesis
3. Gap2
•the time spent in interphase determines the rate of cellular division
14
Q
Gap 1
A
cells replicate organelles and increase volume of cytosol
15
Q
Synthesis
A
DNA duplication is performed
16
Q
Gap 2
A
Centrioles replicate (cell division machinery)
17
Q
G0
A
only occurs in cells that do not replicate (neurons)
•specialized cell functions
18
Q
How does a dividing cell ensure that each daughter cell recieves an exact copy of the parent cell DNA?
A
Through DNA replication
19
Q
3 steps of DNA replication
A
- DNA strands unwind
- DNA polymerase attaches to complimentary DNA nucleotides along each strand (multiple polymerase enzymes will bind DNA)
- Produces 2 identical copies of original DNA
20
Q
What enzyme is responsible for unwinds the DNA?
A
Helicase
21
Q
DNA polymerase •what is it •moves in what direction •what happens to 1 strand •what happens to the other strand
A
- responsible for DNA replication
- 1 direction
- One strand is produced in a continuous fashion
- the other strand is produced in segments and joined together by a “ligase”
22
Q
Interphase
A
- End of G2 phase of cell cycle
* DNA exists as duplicated chromatin
23
Q
Metaphase
A
•Chromosomes align on equator of the cell
24
Q
Centromere
A
Where sister chromatids are connected to eachother
25
Anaphase
* Chromosome and centromere splits
* Chromosome are pulled to opposite poles
* Chromosome movement stops after arriving near the centrioles
26
Telophase
* Marks end of mitosis
* Nuclear division is over
* Nuclear membrane re-forms
* Chromosomes uncoil
27
3 components of the plasma membrane
1. Lipids
2. Proteins
3. Carbohydrates
28
```
Lipids in the plasma membrane
•how much % does it make up
•what type of lipids are present
•arrangement
•function
```
* 42%
* Phospholipids and cholesterol
* Bi-layer
* barrier - maintain differences between outside and inside
29
What is the function of cholesterol in the bi-layer?
it is rigid to it provides structure to the membrane
30
Proteins in the plasma membrane
•how much % does it make up
•2 types
•55%
1. Integral
2. Peripheral
31
Integral proteins
Part of membrane structure that is embedded and cannot be removed easity
32
Peripheral proteins
Bound to inner or outer surface of membrane
33
```
Carbohydrates in the plasma membrane
•how much % does it makeup
•where is it located
•what is it known
•what is it used for
```
* 5%
* associated with outer surface only
* Known as glycocalyx
* used for communication
34
Function of the plasma membrane
* Barrier
| * Selectively permeable-permits the passage of some materials while restricting the passage of others
35
4 types of membrane transport
1. Diffusion
2. Filtration
3. Carrier mediated
4. Vescular transport
36
```
Diffusion
•active or passive
•definition
•what is the driving force
•three types
```
```
•passive
•movement of a substance from an area of high concentration to an area of low concentration
•molecules are in motion
1. Simple
2. Channel mediated
3. osmosis
```
37
Concentration gradient
Difference between high and low concentrations
38
5 characteristics of diffusion
1. Membrane must be permeable to substance
2. small and uncharged molecules diffuse freely across the membrane
3. Substances will move until equilibrium is achieved
4. Concentration gradient is eliminated
5. No net movement of molecules
39
Simple diffusion
Substance can directly penetrate the plasma membrane
| •small uncharged molecules (O2 and CO2)
40
Channel Mediated diffusion
•definition
•what does it use to transport these molecules
•allows passage of...
* Used for the passage of charged molecules/ions
* uses an integral membrane protein (channel)
* small H2O soluable molecules
41
```
Osmosis
•definition
•formula
•low solutes = ___ water
•high solutes = ___ water
```
* Refers to the diffusion of water ONLY
* Solution = solutes (Na++, K++) + solvents (H2O)
* High H2O
* Low H2O
42
3 characteristics of osmosis
1. Movement of H2O across a membrane
2. Membrane is freely permeable to H2O but not solutes
3. Water flows across the membrane toward solution with higher solutes
43
Osmolarity
Total solute concentration in an aqueous solution
44
Tonicity
Describes how a solution affects the cell
45
Hypotonic
•definition
•comparison of solutes and water inside and outside the cell
•what happens to cell
* Less solutes compared to the cell
* less solutes out, more solutes in; high H2O out, low in
* cell swells and can explode (hemolysis)
46
Hypertonic
•definition
•comparison of solutes and water inside and outside the cell
•what happens to cell
* More solutes compared to cell
* more solutes out, less in; high H2O in, low out
* cell shrinks (crenation)
47
Isotonic
* same solutes compared to cell
| * water moves in and out at same rate
48
Filtration
Movement of solutes and solvent through a membrane from an area of high pressure to an area of low pressure
49
Hydrostatic pressure
Force of blood against capillaries; moves fluid and molecules out of blood and into tissues
50
Carrier Mediated
•definition
•2 types
Ions/molecules are carried across membranes by binding to integral membrane proteins
1. facilitated diffusion
2. active transport
51
Facilitated diffusion
•passive or active
•definition
•3 characteristics
```
•passive
•movement down a concentration gradient
1. specificity
2. saturation limits
3. regulation
```
52
2 steps of facilitated diffusion
1. Molecules will bind to receptor on carrier protein
| 2. Carrier changes shape and exposes solute to opposite side of cell
53
Active transport
- dependent or independent on a concentration gradient
- energy?
- Moving substances against or with concentration gradient
- example
- dependent
- requires energy from ATP for transport process
- against concentration gradient
- Movement from low to high
- sodium potassium pump
54
Sodium potassium pump
- principle ions
- Outside the cell
- Inside the cell
- how much is being pumped
- Na+ and K+
- Na+ (high), K+ (low)
- Na+ (low), K+ (high)
- 1 ATP will transport 3 Na+ out of the cell and 2 K+ into the cell
55
Vesicular transport
- definition
- how do things move
- 2 types
Bulk movement of materials
- things move in and out of cells in vesicles
1. Endocytosis
2. Exocytosis
56
vesicles
small membrane bound sacs
57
Endocytosis
- definition
- 3 types
- Substances are imported into the cell (requires ATP)
1. Phagocytosis
2. Pinocytosis
3. Active transport
58
Phagocytosis
- definition
- what are these specialized cells called
- Cell "eating"
| - Macrophages
59
Macrophages
- Specialized cells in phagocytosis
- Professional eaters
- eat bacteria, cellular debris, etc
60
Lysosomes
Contains enzymes to digest material
61
Pinocytosis
- definition
- what does it form
- specific?
- what is generally the target
- cell "drinking"
- pinosomes
- not specific
- fluid
62
Pinosomes
- what are they filled with
- where do they form
- where do they deliver too
- extracellular fluid
- form in plasma membrane that are pinched off
- deliver contents in lysosomes
63
Receptor mediated
- defintion
- 5 steps
- specific form of cell eating
1. specific substances bind receptors on plasma membrane (hormones,etc)
2. Formation of a vesicle at plasma membrane
3. Formation of a vesicle within cytosol
4. Vesicles fuse with lysosomes where substances are removed
5. Empty receptors are carried back to the plasma membrane for reuse
64
Exocytosis
- definition
- what are the waste products
- what can it be coupled with
- Vesicles from within the cell fuse to plasma membrane and discharge contents
- hormones
- endocytosis
65
Cytoplasm
- definition
- 2 things in it
- material between plasma membrane and nuclear envelope
1. cytosol
2. organelles
66
Cytosol
intracellular fluid- nutrients, proteins, ions and wastes
67
Organelles
- definition
- 2 types
performs cellular functions
1. Non-membranous organelles
2. membranous organelles
68
non - membranous organelles
| -4 types
1. cytoskeleton
2. Centrioles
3. Cilia
4. Ribosomes
69
Cytoskeleton
| -3 components
1. Microfilaments
2. Intermediate filaments
3. Microtubules
70
Microfilaments
- structure
- 2 functions
- solid slender rods (6mm in diameter), composed of actin (smallest of filaments)
- 1. Anchor cytoskeleton to plasma membrane
2. Change the shape of the cell
71
Intermediate filaments
- structure
- 2 functions
- stable rods (7-11 nm in diameter), protein composition varies, "intermediate" in size, most durable of all filaments
- Strengthen cell and help maintain shapes
- stabilize positioned of organelles and cell itself
72
Microtubules
- structures
- 5 functions
- hollow tubes (25 nm in diameter), composed of tubulin, largest of the 3 filaments
- 1. Primary component of cytoskeleton
2. Can help change the shape of the cell
3. Can help shuttle vesicles and organelles around cell = "molecular motors"
4. Aid in cell division - moves chromosomes
5. Form structural components of some organelles
73
Centrioles
- definition
- which do not have centrioles
- what is it composed of
- how many groups do they form
- function
- All cells undergoing cell division will have centrioles
- RBC, skeletal muscles, cardiac muscles, neurons
- short microtubules
- form 9 groups each containing 3 tubules (9+3) arrangement
- Form spindle appartatus associated with movement of chromosomes
74
Cilia
- definition
- structure
- function
- Found on cells lining respiratory and reproductive tract
- Long extensions of plasma membrane , 9 pairs of microtubules + 2 in the middle
- 1. Beat to move fluids or secretions across cell surface
2. Waves are synchronized and can move materials very effectively
75
Ribosomes
- 2 things make up ribsomes
- consists of what 2 subunits
- function
- 60% rRNA and 40% protein
- (large and small) Free=cytosol; fixed = ER
- Responsible for protein synthesis
76
Membranous organelles
| -6
1. Mitochondria
2. Rough ER
3. Smooth ER
4. Golgi Apparatus
5. Lysosome
6. Perioxsome
77
Mitochondria
- structure
- 2 functions
- how much percent of ATP is produced
- Has a double membrane, cristae and matrix
1. Energy production
2. Formation of ATP to be used by other cellular structures
- 95%
78
Endoplasmic reticulum
Network of membrane bound sacs and tubes
79
Rough ER
- structure
- function
- surface contains ribosomes
| - responsible for modifying and packaging proteins for export to golgi apparatus
80
Smooth ER
- structure
- 3 functions
- Lacks ribosomes on surface and is more tubular
1. Synthesis of lipids and steroid hormones
2. Glycogen and Ca++ storage
3. detoxification
81
Golgi Apparatus
- structure
- function
- 3 steps
- stacks of hollow (cisternae)
- Recieves newly modified proteins from ER
1. Proteins are modified, sorted and packaged
2. vesicles
3. Exocytosis or other places in cytosol
82
Lysosome
- structure
- 2 functions
- small spherical vesicles
1. contains digestive enzymes that breakdown large macromolecules within cell
2. destroys bacteria that enter cell
83
Perioxisome
- structure
- 2 functions
- very small spherical vesicles
1. Absorb and breakdown fatty acids and other organic compounds
2. neutralizes H2O2 (hydrogen peroxide) formed by fatty acid breakdown (protective function
84
How do protein differ?
order of AA
85
Central dogma
- definition
- 3 steps
Info flows from DNA to RNA to Protein
1. Info in DNA is copied to make a message (contains the code for a protein)
2. mRNA exits nucleus and enters cytoplasm
3. The info in the mRNA is used to assemble a chain of AA
86
DNA
contains instructions for putting AA in the correct order for a particular protein
87
RNA
- definition
- 3 types
Plays a role in expressing this info
1. mRNA
2. rRNA
3. tRNA
88
Gene
-section on a segment of DNA that codes for a particular protein
89
code
- A triplet code
| - Each AA = 3 bases in the DNA
90
Transcription
- definition
- location
- 3 steps
- the production of mRNA from a DNA template
- inside nucleus
1. DNA unwinds and separates (1 strand serves as a template)
2. RNA polymerase travels on template strand and inserts complementary bases of RNA (U will substitute for T)
3. Newly formed RNA exits and DNA strands unite
91
RNA polymerase
binds to template strand and reads DNA template and inserts complementary RNA bases
92
Translation
using the information in mRNA to assemble AA in the correct order to make a particular protein
