Cell Membrane Flashcards

1
Q

What is Homeostasis?

A

a constat stae is maintained

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2
Q

What are the other functions of the cell membrane (minus being semi-permeable)? (3)

A
  • provides structual support
  • recognized foregin materials
  • communicate with the cells
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3
Q

What is the lipid bi-layer

A

the phospholipid’s orgainized ontotowo layers with the hydrophobic tias int eh center and the hydrophilic head facing into and out of the cell.

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4
Q

What can pass throug the bi-layer? Why?

A

small and non polar molecules

Becaue the hydropobic tais will repel any polar substance.

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5
Q

What are the four types of membrane proteins?

A
  • cell recognition: identifys the cell as “self”
  • receptor: receives signals from surroungings
  • enzymatic: helps with biochemical relations
  • transport: moves substances in and out of cell
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6
Q

What is a Membrane Protein?

A

A prtein that interacs with or ar a part of biological memebranes

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7
Q

What are the two types of transport proteins?

A
  • channel-specific particles or ions move freely in or out of the cell
  • carrier - selective interacts with only certain molecules.
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8
Q

What does permeability mean?

A

movement across the cell membrane

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9
Q

What is a concentration gradient?

A

one area has a higher concentration than another

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10
Q

What is diffusion?

A

movement of a substance down their concentration gradient

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11
Q

What is equilibrium?

A

balanced on both sides

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12
Q

What is Passive Transport?

A

no energy required aka diffusion

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13
Q

What are the two types of passive transport? explain.

A
  • facilitated diffusion: movement through channel proteins down a concentration gradient.
  • osmosis: water diffusing across the cell membrane (need channel protein.)
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14
Q

What is Hypertonic?

A

low concerntration of water outside of the cell and a higher concentration of solute.

So water moves out of the cell causing it to shrink

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15
Q

What is Hypotonic?

A

a high concentration of water outside of the cell and a lower concentration of solute.

So water moves in of the cell causing it to swell

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16
Q

What is Isotonic?

A

equal solute concentration and water moves in and out at equal rates.

17
Q

What is active transport?

A

when a substance moves against its concentration gradient. this required a carrier protein and ATP

18
Q

What do carrier proteins act as?

A

pumps

19
Q

What are vesicles?

A

they import and export very large molecules that can’t cross the cell membrane.

20
Q

What are the types of vesicles?

A
  • exocytosis
  • entocytosis
    • phagocytosis
    • pinocytosis
21
Q

What is exocytosis?

A
  • secretion
  • vesicles fuse to the cell membrane and then releases their particles
  • thereby extending the cell wall
22
Q

What is endocytosis?

A

a portion of the cell membrane pinches off to format vesicle

23
Q

What is phagocytosis?

A

large substances like viruses or white blood cells

24
Q

What is pinocytosis?

A

liquid of small substances

- loss of membrane balanced by exocytosis

25
Q

What is receptor-mediated endocytosis?

A

molecules must bind to specific receptor proteins in order for vesicles to for and enter the cell.

26
Q

What are the two purposes of DNA replication?

A
  • growth

- repair

27
Q

What are the four important enzymes in DNA replication? What are their functions?

A
  • DNA helicase: unzips parent strand
  • DNA primase: creates a stating spot for polymerase
  • DNA polymerase: bonds new nucleotides
  • DNA ligase: contents Okazaki fragments and proof reads.
28
Q

What is semi-conservative replication?

A

each daughter strand contains one new strand and one parent strand.

29
Q

Which way do enzymes work? (regarding DNA)

How does this relate to Okazaki fragments

A

5’ to 3’
- the primase has to connect in several spots so the polymerase can work 5’ to 3’ even though the lagging strand’s new chain is 3’ to 5’

30
Q

Describe what the cell growth cycle looks like.

A
  • growth one
  • rest/ chcekpoint (if the cell is not working properly the cell will be told to commit suicide)
  • growth two
  • rest/ checkpoint two
  • prophase
  • mitosis (PMATC)
31
Q

What is a Gene?

A

a segment of DNA that specifies the amino acid sequence of a polypeptide

32
Q

Is DNA directly in control of protein synthesis? Explain.

A

No. its code is copied into RNA and then taken out of the nucleus.

33
Q

What are the three classes of RNA? What are their functions?

A
  • mRNA: takes a message from DNA to the ribosomes
  • rRNA: makes up ribosomes (along with proteins) mRNA slots into it.
  • tRNA: carries amino acid to ribosomes.
34
Q

What is Transcription?

A

making mRNA from a segment of DNA (in the nucleus)

35
Q

In Transcription what are the strands involved called?

A
  • sense strand: the strand being used as a template

- non-sense strand: the strand of DNA not being used.

36
Q

What are the steps in Transcription?

A
  • RNA polymerase binds and unwinds the DNA strand
  • DNA helix is opened so complementary base pairing can occur
  • RNA polymerase joins new RNA nucleotides in a sequence complementary to the sense strand of the DNA
  • creates mRNA