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Bio 1A03 > Theme 1- Module 1 > Flashcards

Theme 1- Module 1 Flashcards

1
Q

What’s so special about prokaryotic cells?

A

They do not contain a true nucleus

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2
Q

Do we have more eukaryotic cells or prokaryotic cells in our bodies?

A

Prokaryotic

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3
Q

What is the microbiome?

A

Population of microbes in our body

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4
Q

Do microbiomes contain only prok cells?

A

No also small eukaryotic cells

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5
Q

What does Strep. Salivarius do and where is it found?

A

Upper respiratory tract + oral cavity

Forms dental plaque

Colonize newborns germfree oral cavity and GI tract

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6
Q

What does Staph. Haemo do and where is it found?

A

When it’s on the skin it’s harmless

When it’s in the body it’s pathogenic

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7
Q

What does Bacteroides thetaiot. do and where is it found?

A

Intestines

Forms enzymes that breakdown ingested plant material

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8
Q

Define a cell

A

Membrane bound structure with macromolecules

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9
Q

What are the macromolecules?

A

Nucleic acids

Proteins

Polysaccharides

Phospholipids

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10
Q

What is the function of proteins?

A

Structure

Metabolic activities (enzymes, ribosome)

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11
Q

Do polysaccharides contribute to structural functions?

A

Yes

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12
Q

Are the tails of a lipid hydrophilic or hydrophobic? Polar or non polar?

A

Hydrophobic

Non polar

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13
Q

Phospholipids are amphipathic. What does that mean?

A

Have both hydrophobic and philic parts

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14
Q

Describe the structure of the fatty acid chains at the end of a phospholipid molecule.

A

16 or 18 carbons in a chain

Single or double bonds

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15
Q

Are single bonds saturated or unsaturated? Why is this important?

A

Saturated

The bond types change the shape and behaviours of the phospholipid and thus the membrane

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16
Q

True or false: Phospholipids are the only types of lipids found in cell membranes. If false, state the other lipids

A

False

Steroids

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17
Q

Describe the structure of steroids and give an example

A

4 hydrocarbon ring

Hydrophilic head
Phobic tails

Cholesterol

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18
Q

True or false: phospholipids only form lipid bilayers. If false, state what other structures they form

A

False

Can aggregate and form micelles

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19
Q

Do micelles need energy to form?

A

No

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20
Q

What role do micelles play in the human body?

A

Absorption of fat soluble vitamins and complex lipids

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21
Q

True or false: phospholipids are not stationary. Explain

A

True

Membranes are fluid

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22
Q

How do phospholipids typically move within membranes

A

Laterally within one layer

CANNOT flip from one layer to the other tho with a lot of energy

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23
Q

What are the 4 factors affecting the fluidity of membranes?

A

Number of carbons in the fatty acid tail

Unsat or sat fatty acids

Temperature (or other environmental factors)

Presence or absence of cholesterol/steroids

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24
Q

If there were 18 carbons in the carbon chain rather than 16, how would that change the membrane?

A

Longer chains pack together tighter and reduce fluidity

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25
If there were double bonds in the carbon chain, how would that affect the structure and function?
Produce kinks Push neighbouring phospholipids further apart Increase fluidity Affect permeability
26
What affect does temp have on the membrane?
High temp = more fluid Low temp = less
27
Do cold adapted organisms have more unsat or sat phospholipids? Why?
Unsat Maintain fluidity
28
What affect does chloresterol have on fluidity at normal temperatures? Why is this important?
Steroids pack closely to neighbouring phospholipids Constrain fluidity (JUST phospholipids = TOO much fluidity)
29
Why are steroids important for fluidity at lower temperatures?
Phospholipids solidify at low temps Cholesterol maintain fluidity by keeping apart
30
Is fluidity consistent throughout the entire membrane? Give an example of a domain that might be different
No Lipid rafts
31
Are lipid rafts regions of high fluidity or low fluidity?
Low
32
What is the function of a lipid raft?
Hold macromolecules together in the membrane Gather proteins involved in same metabolic pathway or a collection of receptors found on surface of cell
33
Why do lipid rafts have low fluidity?
1) Phospholipid tails are straight (saturated) --> pack together and lower fluidity 2) Higher conc of cholesterol
34
Why are lipid rafts taller than the rest of the membrane?
Carbon chains are longer
35
Why is low fluidity important in lipid rafts?
It allows them to hold the macromolecules
36
Macromolecules move _______ within the cell membrane
Laterally
37
Why is fluidity important in transmembrane movements?
Changing fluidity alters how much and how quickly a substance will move across the membrane (permeability)
38
Would regions of the membrane that have LESS unsat fatty acids and MORE cholesterol be less permeable or more?
Less bc less fluid membrane
39
Which substances can pass thru the membrane without additional energy?
Small, nonpolar (hydrophobic) molecules or ions
40
Which substances CANNOT pass thru the membrane without energy?
Large, charged polar molecules
41
How do small molecules cross the membrane?
Along a concentration gradient via diffusion
42
True or false: Cell membranes contain only lipids and proteins
False Also contain carbs
43
How do hydrophilic molecules pass in and out of the cell?
Via transmembrane (integral membrane) proteins embedded within the cell membrane
44
What does the fluid mosaic model state?
Membranes consist of proteins and carbs embedded in a fluid bilayer
45
What does the fluid mosaic model predict?
Predicts certain properties of the cell membrane (i.e. The ability of membrane components to move laterally)
46
What are the three diff types of transport across cell membranes?
Passive diffusion Facilitated diffusion Active transport
47
What the difference between passive diffusion and facilitated diffusion?
Both involve the movement of molecules along a conc gradient but... Passive = molecule coming into contact with the phospholipid layer Facil = proteins embedded in the membrane allow the molecules thru
48
Does passive transport require energy?
No
49
What is active transport?
Movement of molecules AGAINST conc gradient Embedded proteins require ATP (energy) to drive the transport
50
What is the most common way for substances (i.e. Water) to move passively across cell membranes?
Facilitated diffusion (passive transport)
51
How do transport proteins help large hydrophilic molecules pass the membrane?
Provide a hydrophilic core for them
52
What is osmosis?
Movement of water across a membrane (PASSIVE transport)
53
How does water diffuse across a selectively permeable membrane via a conc gradient?
From a less conc solution (HYPOTONIC) to a more conc solution HYPERTONIC)
54
If you placed a cell in a HYPERtonic solution what would happen?
Less water on outside so it would shrivel up as water goes out of it
55
If you placed a cell in a HYPOtonic solution what would happen?
It will become swollen (less water on inside compared to outside)
56
What are aquaporins and what are their functions?
Transmembrane proteins that allow water to move across membrane at a much faster rate than it could via simple diffusion
57
How do aquaporins allow water to move along so fast? (i.e. What structural components)
Allow ONLY water to pass thru a hydrophilic protein core thru the process of osmosis
58
True or false: the movement of water across a aquaporin does not requires energ
False
59
After placing a cell in a hypotonic solution, it bursts. What remains?
Ghost cells
60
Where does the energy for active transport come from?
The hydrolysis of ATP on the intracellular side of the cell
61
What is PRIMARY active transport?
Transmembrane transport protein is DIRECTLY affected by the hydrolysis of ATP TT protein changes to pump the substance across
62
What is SECONDARY active transport?
INDIRECT expenditure of ATP entry Neighbouring TTproteins use the electrochemical gradients established by primary active transport pumps to move their own solutes against a conc gradient
63
What are the similarities between primary and secondary active transport?
Both require energy Both work against conc gradient
64
What kind of active transport does the sodium potassium pump use?
Primary active transport
65
True or false: in most cells, there is a greater conc of sodium in the interior fluid
False Sodium greater on OUTSIDE Potassium greater in INSIDE
66
How does the sodium-potassium pump work?
For every 3 sodium ions pumped OUT, 2 potassium ions pumped IN Goes against conc gradient, so ATP gives up phosphate group to TTprotein Phosphate group binds and causes a conformation change in shape of protein Allows for release of sodium ions Potassium from outside binds to TTprotein, causes original phosphate group to be released Protein returns to original shape Releases potassium into cytoplasm
67
What are hopanoids?
Five ringed structures in PROKARYOTES that serve a similar function to cholerestrol
68
True or false: most prokaryotes can synthesize sterols such as cholesterol
False Synthesize hopanoids instead
69
Instead of a nucleus, what do prokaryotes have instead?
Nucleoid | = cell structure with multiple loops formed from supercoils of DNA
70
How are genes for antibiotic resistance commonly transferred thru bacteria?
Pili (threadlike structures that extend from one cell to another) transfer plasmids (and thus, genes) between bacteria
71
What is the function of the ER?
Synthesizes proteins and lipids
72
What is the function of the Golgi body?
Modifies proteins and lipids produced by ER Sorts them out to destinations
73
What is the function of the Lysosome?
Contains enzymes that break down macromolecules
74
What is the function of Peroxisomes?
Contains enzymes involved in metabolism - breakdown of fatty acids - synth of certain types of phospholipids
75
What is the function of the mitochondria?
Produce most of the ATP/energy
76
What is the function of vacuoles (in plants)?
Maintain turgor pressure against cell walls and contribute to structural rigidity
77
What is the function of plasmodesmata (in plants)?
Connect neighbouring plant cells

Bio 1A03 (18 decks)

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