Cells Flashcards

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1
Q

What is diffusion

A

Diffusion is the movement of molecules from an area of high concentration of the molecules to an area with low concentration down a concentration gradient

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2
Q

What happens to molecules during diffusion

A

During passive diffusion a molecule simply dissolves in the phospholipid bilayer diffusion across it and then dissolves in the aqueous solution at the other side of the membrane

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3
Q

How does diffusion happen

A

Diffusion happens when molecules of gas or liquid spread out.

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4
Q

Does diffusion require energy

A

Diffusion doesn’t require energy as it is a passive process

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5
Q

How does oxygen move into cells

A

Oxygen moves into the cells by diffusion and diffuses across the cell membrane

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6
Q

How does carbon dioxide move out of cells

A

Carbon dioxide moves out of cells by diffusion and diffuses across the cell membrane

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7
Q

What is a selectively permeable membrane

A

A semi permeable membrane will let molecules pass through if they are small enough. Larger molecules cannot pass through the pores in the membrane

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8
Q

What membrane is the cell membrane

A

The cell membrane is a semi permeable membrane

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9
Q

Remember!

A

During experiments, the visking tubing can be used as a model of the cell membrane. The pore size in visking tubing is large enough to allow small molecules through such as iodine or water molecules. SOLUTES molecules such as starch are too large to pass through

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10
Q

What is meant by the term semi permeable membrane

A

It allows small/ smaller molecules to pass through

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11
Q

Identify which molecules pass through the visking. Explain your answer

A

The small balls can pass through but the big balls are too big for them to fit through the visking tubing

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12
Q

Explain why the colour of the contents inside the visking tubing turned blue/black

A

Iodine is small.
Diffuses into visking tubing.
Reacts with starch which is presented to give the blue and black colour

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13
Q

Explain why the colour of iodine solution in the boiling tub did not change.

A

Start is large. Cannot pass through the membrane or fit through the pores

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14
Q

Name one substance required for respiration that would pass through into a cell

A

Oxygen or glucose

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15
Q

Write down one way that diffusion and osmosis are similar

A

They both are from a high to a low concentration gradient

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16
Q

Write down one way that diffusion and osmosis are different

A

Osmosis travels through a semi permeable membrane however diffusion is travelled down a concentration gradient

17
Q

What is osmosis

A

Osmosis is the movement of water from a high to a low concentration and water molecules move through a semi permeable membrane this means that water molecules move down a concentration gradient

18
Q

Does osmosis require energy

A

Osmosis doesn’t require energy as it is a passive process

19
Q

What are two ways that active transport is different to diffusion and osmosis

A

Active transport is from a low to high concentration however diffusion and osmosis are from a high to low concentration. For active transport you need energy but for osmosis and diffusion you dont

20
Q

What is active transport

A

Active transport is the process where substances move from a low to high concentration against a concentration gradient active transport requires energy in form of ATP the energy is released from respiration if respiration stops active transport will stop as there is no everything available

21
Q

What is enzymes

A

Enzymes are proteins that are made by living cells enzymes are “biological catalysts” they speed up the rate of chemical reactions that take place within cells.

22
Q

What substrate is the “lock”

A

The enzyme is the lock

23
Q

What substrate is the “key”

A

The substrate is the key

24
Q

What is formed when these two substances fit together

A

They form into enzymes/substances complex