Chapter 1: Cells Review Flashcards
1
Q
What is homeostasis?
A
Homeostasis is the process in which a cell or organism maintains its internal environment at equilibrium even though the external environment changes.
2
Q
Why is the Surface Area to Volume ratio important?
A
The cell needs enough surface area to supply material or remove wastes from the metabolically active cytoplasm.
3
Q
What is the surface area equation?
A
6L^2
4
Q
What is the volume equation of a cell?
A
L^3
5
Q
The internal volumes …? at a greater rate than the surface area of their plasma membrane
A
increase
6
Q
What happens beyond a given cell size?
A
The two way exchange of materials cannot occur fast enough to sustain the cell.
7
Q
What are prokaryotic cells?
A
They are simple cells that lack a nucleus and membrane bound organelles.
8
Q
What kingdoms do prokaryotic cells belong to?
A
Bacteria
9
Q
What are eukaryotic cells?
A
Complex cells that contain a nuclear envelope or membrane and also contains membrane bound organelles.
10
Q
What kingdoms do eukaryotic cells belong to?
A
Animal, plants, fungi and protists.
11
Q
Similarities between prokaryotes and eukaryotes.
A
Contain genetic information have plasma membranes CHONP Produce proteins Use ATP
12
Q
Distinguish differences between prokaryotes and eukaryotes.
A
Prokaryotes: . No membrane bound organelles . No nucleus . Simple . Unicellular . Smaller Eukaryotes: . Membrane bound organelles . Nucleus . Complex . Larger . Majority multicellular
13
Q
What is the width of the plasma membrane?
A
4-10nm
14
Q
What is the plasma membrane?
A
An active boundary that separates the internal environment from the surroundings and can exclude the entry of substances, permitting entry of some and eliminating others.
15
Q
What does semi-permeable mean?
A
Allows only some substances to cross in and out.
16
Q
What are the two major components of the plasma membrane?
A
. Phospholipids- The main structural component
. Proteins- embedded in the membrane
17
Q
The plasma membrane consists of …? of phospholipids?
A
. Double Layer (Bi layer)
18
Q
What can the phosphate head be described as?
A
Hydrophilic, polar
19
Q
What can the fatty acid tails be described as?
A
Hydrophobic, non-polar
20
Q
What is hydrophobic?
A
Water fearing
21
Q
What id hydrophilic?
A
Water loving
22
Q
Why do the hydrophobic tails face each other?
A
Because the water repels the fatty acid tails. Water and oils do not mix.
23
Q
What state are fatty acids at body temperature?
A
Liquid
24
Q
Define viscous
A
Having a thick, sticky consistency between solid and liquid
25
What can proteins be grouped into in the cell membrane?............./..........
```
. Integral proteins:
- Adhesion
- Receptor
- Enzymatic
- Transport
. Peripheral proteins
```
26
What are integral proteins?
Fundamental components of the membrane. They are embedded in the phospholipid membrane and typically span the width of the membrane. (trans-membrane).
27
What are glycoproteins?
Carbohydrate groups, such as sugars, are attached to the exposed part of the proteins on the outer side.
28
What are peripheral proteins?
Proteins anchored to the exterior of the plasma membrane through bonding with lipids or are indirectly associated with the plasma membrane with interactions with integral proteins.
29
Why is "fluid" used to describe the cell membrane?
Because the fatty chains of the phospholipids are viscous or like a thick oily liquid.
30
Why can the cell membrane be described as "mosaic"?
The external surface has the appearance of a mosaic as because of the various embedded proteins set in a uniform background.
31
What are the functions of the plasma membrane?
1. An active and selective boundary
2. Denotes cell identity
3. Receives external signals
4. Transports materials
32
What is the cell theory?
1. All organisms are composed of cells.
2. Cells are the smallest living things.
3. Cells all arise from pre-existing cells.
33
Which organelles are membrane bound?
. Nucleus
. Smooth and Rough endoplasmic reticulum
. the Golgi apparatus
. lysosomes
34
Which organelles have an internal and external membrane?
. Mitochondria
| . Chloroplasts
35
Are ribosomes membrane bound?
No
36
What is the function of the nucleus and where is it found?
It is found central in animal cells and next to the large vacuole in plant cells in the cytosol. It contains the nucleolus and contains genetic information for cell function and protein synthesis.
37
What is the function of mitochondria and where are they found?
Mitochondria are responsible for the generation of energy for the cell's use through cellular respiration and is found freely in the cytosol.
38
What is the function of ribosomes and where are they found?
The ribosomes are composed of proteins and rRNA and synthesises proteins from and mRNA transcript, by the process of translation. It is dispersed in the cytosol or attached to the endoplasmic reticulum.
39
What would happen to the phospholipids if it was cold and there was no cholesterol?
. Phospholipids cluster together
. Less Movement
. Less Energy
. Too rigid and might break
40
How does the cholesterol help the cell membrane in cold climates?
Acts as a buffer and regulates fluidity by interrupting bonds between tails, therefore loosening the membrane.
41
What would happen if the phospholipids were in a hot climate without cholesterol?
```
. Phospholipids spread out
. More movement
. More energy
. Too fluid
. Can't hold its shape
```
42
How does cholesterol help the cell membrane in hot climates?
Acts as a buffer and regulates fluidity be interrupting bonds between tails, therefore reducing movement.
43
What is the process of glycocalyx?
the process of the cell denouncing cell identity through glycoproteins or glycolipids.
44
What does saturated mean?
Single bonds only (max no. of hydrogens)
45
What does unsaturated mean?
One or more carbon-carbon multiple bonds.
46
What forces hold phospholipids together?
Weak dispersion forces
47
What do glycoproteins on the outer plasma membrane function as?
Cell surface markers-denounce cell identity as "self".
48
What are transmembrane proteins on the outer shell?
Receptors
49
What happens when a signal binds to a receptor?
Alters shape and initiates a response
50
Who do multicellular organisms use receptors with?
other cells
51
Who do unicellular organisms use receptors with?
Outside environment
52
What can cross the cell membrane through simple. diffusion?
. Small molecules
. Uncharged molecules
. Lipophilic/hydrophobic
. Movement down the gradient
53
Define simple diffusion
The passive net movement of substances across the phospholipid bilayer from a region of high concentration of solute to a region of low concentration of solute.
54
Define Solute
A substance that can be dissolved in solvent (water) to form a solution.
55
Define solvent
Liquid such as water
56
Define solution
Combination of solute and solvent
57
Define osmosis
The passive net movement of water across the semipermeable membrane from a solution of lesser solute concentration to one of greater concentration.
58
Define Hypotonic
having a lower solute concentration than the cell's contents.
59
Define Isotonic
having an equal concentration to that of cells
60
Define hypertonic
having a higher solute concentration than the cell's contents.
61
What is turgid?
Rigidly swollen
62
When an animal cell is in a hypertonic solution it is?
Shriveled
63
When an animal cell is in isotonic solution it is?
Normal
64
When an animal cell is in hypotonic solution it is?
Lysed
65
Define Lysed
the disintegration of a cell by rupture of the cell wall or membrane.
66
What is a plant cell in a hypertonic solution?
Plasmolyzed
67
Define plasmolyzed
The contractor of the cell membrane from the cell wall.
68
What is a plant cell in isotonic solution?
Flaccid
69
Flaccid meaning
A plant cell that os limp from the reduction in pressure within the cell.
70
What is a plant cell in hypotonic solution?
Turgid (normal)
71
Define Turgid?
A plant cell fully inflated by water.
72
What is the difference between ethanol and urea crossing, and water and gases (CO2) crossing?
Urea and ethanol dissolve through the phospholipid bilayer as they are non-polar and hydrophobic. Water and gases move through gaps (pores) in the bilayer. Both simple diffusion.
73
Define Facilitated diffusion
Involves protein transporters and is the means of transport of dissolved hydrophilic substances down the concentration gradient.
74
Define channel protein
a transmembrane protein that is hydrophilic on the inside and hydrophobic on the outside. Different channel proteins are specific for the diffusion of charged particles or charged polar molecules.
75
What gradient do ions move down?
ELECTROCHEMICAL! (not concentration)
76
How do carrier proteins function?
. Binds with specific molecule
. Protein undergoes a change in shape
. Delivers cargo to other side
77
True or false: Carrier proteins are specific.
True
78
What happens the higher the concentration gradient in simple diffusion?
A faster rate of simple diffusion.
79
What happens in facilitated diffusion the higher the concentration gradient?
The steeper the gradient, the faster the rate of facilitated diffusion, BUT ONLY TO A CERTAIN POINT.
80
What modes of transport does water use?
Osmosis and facilitated diffusion
81
What happens to the rate of facilitated diffusion when all proteins are saturated?
Plateaus?fletlines
82
Define active transport
Active transport moves dissolved substances from a region of low solute concentration to a region of high solute concentration with the input of energy, typically adenosine triphosphate.
83
What are the proteins called that are involved in active transport?
Pumps
84
What are the functions of a pump?
. Transports one or two specific substances
| . Has both a transport and enzyme function
85
What does the enzyme function do. in the pump?
Catalyses energy-releasing reaction.
86
What are the essential regulations of a protein pump?
. pH balance
. Regulation of cell volume
. Uptake of needed nutrients
87
What are some examples of active transport?
. Uptake of dissolved mineral ions in root cells
. Secretion of H+ ions out of stomach cells
. Uptake of glucose in the small intestine into the cells, Na+ and C6H12O6 pump
. SODIUM AND POTASSIUM PUMP
88
How many Na+ and K+ ions does 1 ATP molecule transport in the sodium-potassium pump?
3 Na+ out
| 2 K+ in
89
How is a sodium-potassium pump involved in a nerve impulse?
Sodium ion channels open and sodium ions rabidly flood in by facilitated diffusion. After impulse has passed, sodium channels close. K+-Na+ pump restores levels back to normal.
90
What is Cystic Fibrosis?
An inherited disorder where the protein channel that normally allows chloride ions (Cl-) to move out of cells is affected or faulty.
91
What are the effects on the lungs in cystic fibrosis?
. The movement of Cl- ions out of cells into lung cavity no longer occurs
. Stops the consequent flow of sodium ions
, Stops osmotic flow of water in the lungs that normally thins mucus
92
What are the consequences of the non existent osmotic flow in the lung cavity?
Causes unusually thick, sticky and difficult to move mucus
93
What are some other effects of Cystic Fibrosis?
. Sweat glands usually reabsorb salt however doesn't happen and results in very salty sweat.
. In the pancreas the mucus blocks the digestive ions from travelling through a tube.
94
What is cholera?
A disease resulted from a bacterial infection of vibrio cholera. A toxin produced by this bacteria causes the chlorine ion channels in the intestine to be locked on open.
95
In cholera, what are the resulting effects of the toxin?
The flood of sodium and chloride ions into the intestine through the electrochemical gradient causes a hyper osmotic environment and draws large amounts of water out and thus causing diarrhoea.
96
Define endocytosis
The movement of bulk macromolecules and fluids into the cell.
97
Define Exocytosis
The movement of bulk macromolecules out of the cell
98
Define Receptor Mediated endocytosis
A trigger has to occur before a receptor will assist the entry of material into the cell.
99
Define phagocytosis
The process in which solid particles are ingested
100
Define Pinocytosis
The processes by which liquids/solutions are ingested by the cell.
101
Is cytosis passive or active?
Cytosis is a form of active transport as it requires adenosine triphosphate.
102
What is the function of the Golgi apparatus and where is it found?
The Golgi apparatus is found in the cytosol above the nucleus and it modifies, packages and exports proteins out of the cell.
103
What is the function of the cell wall and where is it found?
The cell wall surrounds the cell and provides protection, strength and support.
104
What is the function of Rough Endoplasmic Reticulum and where is it found?
Prepares proteins to be transported around the cell and is in the cytosol.
105
What is the function of Smooth Endoplasmic Reticulum and where is it found?
Lipid and carbohydrate synthesis and is found in the cytosol.
106
What is the function of a lysosome and where is it found?
Lysosomes are found in the cytoplasm and digests food particles, wastes, cell parts and foreign materials.
107
What is the function of the cytoskeleton and where is it found?
It is found underneath the membrane and helps maintain shape and is important for cell mobility.
108
What is the function of chloroplasts and where are the found?
In the cytoplasm of plant cells and some bacteria. This is the site of photosynthesis where oxygen and glucose is produced.
109
What is the function of a centriole and where is it found?
Helps with cell division and he formation of spindle fibres and is located in cytoplasm.
110
What is the function of the large vacuole and where is it found?
Stores water and other liquids and supports the plant cells. Found in the centre of plant cells.
