Unit 5: cell membrane transport and excretory sytem Flashcards

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1
Q

diffusion

A

big idea: things spread out definition: The movement of particles down their concentration gradient.

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2
Q

osmosis

A

the diffusion of water

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3
Q

hypertonic

A

a more concentrated environment water will move out of the cell and into this environment

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4
Q

hypotonic

A

a less concentrated environment water will move out of this environment and into the cell

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5
Q

isotonic

A

an equally concentrated environment the cell will be unaffected

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6
Q

Why do crackers go stale?

A

They are hypertonic. Water moves from the air to the cracker.

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7
Q

Why can’t we drink sea water?

A

Sea water is hypertonic to our cells. We get dehydrated.

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8
Q

Why is soil salinity a problem?

A

As farmers irrigate their fields, sometimes a little salt was in the water. The water is used by the plants and evaporated into the air, but the salt stays behind and its concentration increases each season. Eventually the soil will be hypertonic and no crops will grow.

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9
Q

Why use saline solution instead of water?

A

Putting water directly into your eyes or veins would make a hypotonic environment for our cells. It does not feel comfortable. Saline solution is isotonic to our cells.

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10
Q

Why are cells so small?

A

A smaller cell has a higher surface area to volume ratio. This means it has more cell membrane (ability to feed itself) than body (need for food). Bigger cells are less able to get nutrients to all parts of the cell.

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11
Q

passive transport

A

the movement of particles in or out of the cell without using energy. Could be by diffusion, osmosis, or by facilitated diffusion

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12
Q

facilitated diffusion

A

a protein in the cell membrane acts as a channel, allowing a certain kind of molecule to diffuse in or out of the cell freely.

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13
Q

active transport

A

the movement of particles in or out of the cell using energy. Could be by protein pump or by cytosis

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14
Q

protein pump

A

A protein in the cell membrane which uses energy to push a particle in or out of the cell. The pump can be used to push the particle up its concentration gradient.

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15
Q

endocytosis

A

Large molecules and viruses can attach to receptor proteins which signal the cell membrane to enfold. The fold wraps around the large molecules and pinches off, creating a vacuole inside the cell.

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16
Q

exocytosis

A

a vesicle leaves the golgi and combines with the cell membrane, dumping its contents outside the cell.

17
Q

components of the cell membrane

A

phospholipids, proteins, cholesterol

18
Q

phospholipid

A

a hydrophilic phosphate head is attached to two hydrophobic fatty acid tails.

19
Q

fluid mosaic model

A

the cell membrane is not solid. It is a liquid (fluid) with proteins, cholesterol, and other components drifting within the phospholipid bilayer. Because it is composed of so many different pieces, it is called a “mosaic.”

20
Q

How does canning preserve food?

A

The food is sealed within a can or jar and heated to denature all germs. The contents of the jar or can are sterile until opened.

21
Q

How does pickling preserve food?

A

The food is soaked in vinegar (acetic acid). The acid denatures all germs. The food is sterile until removed from the acid.

22
Q

How does drying preserve food?

A

Dried fruits and meats are a hypertonic environment. Germ cells land on the food. The food is more concentrated than the cell, so water leaves the cell. Germs become dehydrated and die.

23
Q

How does salting preserve food?

A

Salted meat and fish are a hypertonic environment. Germ cells land on the food. The food is more concentrated than the cell, so water leaves the cell. Germs become dehydrated and die.

24
Q

What are the organs of the excretory system?

A

kidneys, ureter, bladder, urethra

25
Q

nephron

A

the filtration system inside the kidney

26
Q

How does the nephron work?

A

all the contents of the blood (except for the blood cells) is squeezed into the start of the nephron (Bowmans capsule). Through a combination of active and passive transport, nutrients and salts are reabsorbed while urea is concentrated in the tubule.

27
Q

What can and can’t cross the cell membrane by diffusion?

A

CAN: small molecules such as water, oxygen, carbon dioxide, amino acids CAN’T: salts, large molecules like proteins

28
Q

osmoregulation

A

the regulation of water and salt inside the body to maintain a stable isotonic environment

29
Q

Why do plants, bacteria, and fungi do better than animals in a hypotonic environment?

A

They have cell walls! Animal cells will burst.

30
Q

Why are water drinking contests dangerous?

A

Fresh water is hypotonic to our cells. Too much of it creates a hypotonic environment and our cells burst.

31
Q

How do other animals use their excretory systems to cope with harsh environments (salt water, fresh water, desert)?

A

Their excretory systems are designed to conserve water (for dry or hypertonic environments) or to release extra water (hypotonic environment). Marine animals and plants also have salt glands to excrete out the extra salt by active transport.

32
Q

Solute

A

Particles that are dissolved in water, like salt, sugar, or alcohol.