1.2-1.4: cells Flashcards

1
Q

Liquid outside cell name

A

Extracellular fluid

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2
Q

Plasmalemma

A

Cell membrane

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3
Q

Fluid within cell

A

Intracellular fluid: cytosol

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4
Q

Where do cells come from?

A

Division of pre-existing cells

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5
Q

What are the levels of stuff in body

A

Cellular level-> tissue evel-> organ level-> system level-> organism level

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6
Q

What are the main functions of the cell membrane?

A
  1. physical isolation between inside and outside of cell
  2. regulation of the flow of substances in and out of the cell
  3. sensitivity to the environment and structural support(defines cells and its compartments).
  4. It ensures that the cell is maintained under homeostatic conditions.
  5. Helps identify the cell to other cells
  6. Participates in intercellular signalling
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7
Q

What components make up the cell membrane?

A
  • phospholipid bilayer
  • cholesterol
  • proteins
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8
Q

Cell membrane is

A

a semi-permeable boundary between extracellular and intracellular environment

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9
Q

Structure of phospholipid bilayer

A

hydrophilic head and hydrophobic tail

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10
Q

Amphiliphilic molecules/ amphipalic

A
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11
Q

self arranging properties of phospholipids

A

molecullues spontaneuously alighn to form a waterproof barrier (aligns by themselves without use of energy

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12
Q

Cholesterol structure

A
  • has a hydrophilic and hydrophilic region
  • interacts with fatty acid chains-> strengthens the bilayer, making it less fluid and less permeable.
  • ## maintains membrane fluidity (prevents low temp from making membranes rigid and prevents higher temperatures from increasing fluidity)
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13
Q

Membrane proteins structure and functions

A
  • integral span membrane
  • peripheral- bound to membrane surface
  • receptors
  • transport proteins
  • enzymes
  • cell adhesion molecule (stick cells tgt)
  • cell surface identity markers (e.g. immunity, blood cells, organ transportation)
  • attachment to cytoskeleton/ extracellular matter
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14
Q

Glycocalyx

A

Sugars stuck on proteins

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15
Q

Membrane fluidity is due to the movement of:

A

Fatty acid tails

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16
Q

Which of protein, lipids, ions, water, and carbohydrate can and cannot pass through the cell membrane?

A

protein can’t pass, lipids can, ions can’t, water can (small- can squeeze while they’re moving), carbohydrates cannot

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17
Q

What are some examples of small polar molecules?

A

H2O, urea

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18
Q

What are some examples of large polar molecules?

A

Glucose, amino acids

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19
Q

simple diffusion

A

movement of molecules from an area of high concentration to an area of lower concentration down a concentration gradient.

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20
Q

osmosis

A

diffusion of water across a selectively permeable membrane.

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21
Q

What are the two classes of proteins that mediate facilitated diffusion?

A

Channel proteins, carrier proteins

channel: selective on size and charge (larger than ion cant pass), water protein channel (aquaporin), doesn’t require energy
carrier: integral proteins, selective for certain molecules (e..g nucleotides, glucose), changes shape and releases substance into the cell, doesn’t require energy

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22
Q
A

number of available channel proteins affects the rate of diffusion

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23
Q

Why would a cell spend energy transporting an ion against its concentration gradient?

A

Firstly, this helps maintain homeostasis within the cell. Cells also use this mechanism to regulate the distribution of positive and negatively charged ions between the cytoplasm and extracellular fluid. This creates an “electrochemical gradient” across the membrane and is referred to as resting membrane potential. This difference in charge (voltage) across the membrane is particularly important in excitable cells, such as neurons and muscle cells. Signalling events can trigger rapid movement of ions down their electrochemical gradient and allows cells to transmit signals very quickly (eg. nerve cells can communicate or muscle can contract). Investing energy in transporting these ions is therefore critical.

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24
Q

active transport

A

process of moving molecules or ions across a membrane against their concentration gradient
e..g reabsorption of ions from urine

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25
Q

ATP consists of

A

nucleotide (adenine, sugar(ribose, three phosphate groups

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26
Q

Hydrolysis

A

water is used to break one phosphate off to form adenosine diphosphate

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27
Q

atp is an

A

univeral cellular energy carrier

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28
Q

Explain the process of how 3 sodium ions can be expelled out of the cell and potassium ions be welcomed into the cell.

A
  1. 3 sodium ions from the cytosol bind to the inside surface of the NaK pump
  2. Na+ binding triggers ATP to bind to the pump and be split into ADP AND P. The energy from ATP splitting causes the protein to change shape, which moves the Na+ to the outside.
  3. 2 potassium ions land to the outside surface of the pump and cause the P (from the atp splitting) to be released
  4. The release of the P causes the pump to return to its original shape, which moves the K+ into the cell
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29
Q
A

distal convoluted tubule of the kidney

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30
Q

Secondary active transport

A
  • doesn’t include ATP
  • uses the energy stored by the electrochemical gradient to move secondary substances against their concentration gradient
  • may involve movement of the secondary substances in the same direction (via a symporter) or opposite direction (antiporter)
  • resting membrane potential

drags along other substances
more positive outside the cell than inside
- co transport other molecules against their concentration gradient

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31
Q

Two ways of Vesicular transport and how it works

A

Endocytosis and exocytosis
- involves vesicles to transport cargo out of or into the cell

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32
Q

three ways of endocytosis

A

phagocytosis (cell eating)
pinocytosis (cell drinking)- liquid
receptor-mediated endocytosis- triggered absorption by receptor

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33
Q

pseudopodia

A
34
Q

receptor mediated endocytosis

A

bind to receptors causing change in membrane, little proteins on outside help deal with whatever was gobbled up

35
Q

how does exocytosis occur?

A

membrane of vesicle merges cell membrane of cell and stuff gets spotted out

36
Q

chromatin

A

store of DNA inside the nucleus

37
Q

Function of the nuclear envelope

A
  • forms the outer boundary of the nucleus and encases the nucleoplasm
  • double membrane with space between the two
38
Q

regions of chromatin

A
  • euchromatin (the more pale of this there is, there more transcriptionally active that cell is
  • heterochromatin (the darker areas that are transcriptionally inactive
39
Q

What does the nucleoplasm consist of?

A

ions, enzymes, RNA and DNA nucleotides
- nuclear matrix- cytoskeleton for nucleus

40
Q

nucleosus

A
  • transient nuclear organelles that synthesise ribosomes
  • composed of rna, enzymes, nd histones (proteins)
  • most prominent in cells that produce large amount of proteins, e.g. liver, nerve, muscle cells
41
Q

Nucleotide structure

A

sugar and phosphate groups form covalent bond and form the backbone of the double helix
two chain of DNA are held together as a complementary pair by hydrogen bonds between nitrogenous bases.

42
Q

direction of dna strand

A

one strand runs in direction of five prime to three prime and the other one opposite.

43
Q

nucleosomes

A

dna strands coiled and wrap around histone.

44
Q

how do dna form chromatin?

A
  • dna strands coil and wrap around histone to form nucleosomes
  • nucleosomes loosely coil forming a tangle of fine filaments known as chromatin
45
Q

what do you call tightly compacted chromatin?

A

heterochromatin

46
Q

what do you call loosely packed chromatin?

A

euchromatin

47
Q

how do chromosomes form?

A

At the beginning of cell division, DNA coiling becomes tighter and compact, forming distinct structures called chromosomes.

48
Q

gene

A

portion of dna that codes for a functional gene product
- contains instruction to prouc protein or non coding rna sequences

49
Q

a gene consist of

A

exons (coding regions) and introns (non-coding regions)
intron cut out, exons stuck together for proper blueprint before release of mRNA

50
Q

protein synthesis

A

dna unzips
one strand used for copy of mrna- transcription(everything the same except thymine-> uracil)
mrna leaves nucleus
ribosome reads codons and translates into amino acids

51
Q

The DNA backbone is held together by _______ bonds between the sugar and phosphate groups. Nitrogenous bases are held together by _________ bonds.

A

Hydrogen, covalent

52
Q

phospholipid bilayer fill in

A

photos

53
Q

Why does a cell need to be able to control its internal environment?

A

In order to maintain homeostasis(A state of balance among all the body systems needed for the body to survive and function correctly) and respond to changes in the external environment.
- enzymes need to be at a certain pH to function normally and properly
- intracellular concentration of ions needs to be regulated
- maintain osmotic pressure
- membrane potential

54
Q

How does the plasma membrane enable cells to control its internal environment?

A

It regulates the composition of cytosol by acting as a physical barrier and regulating the entry and exit of of various molecules via channels and transport proteins.
Cell surface receptors relay information to the cell interior, enabling the cell to respond to environmental changes efficiently.

55
Q

how does the long DNA strand get fitted into the nucleus?

A

wrapped around histone protein

56
Q

What is the nuclear envelope?

A

Double membrane surrounding nucleus

57
Q

what is the nucleoplasm

A

fluid, gel like substance in nucleus

58
Q

what does the nucleoplasm do?

A

maintains shape/ structure of nucleus, suspension medium (stuff that keeps substances evenly distributed) for nuclear contents (chromatin, ions, enzymes, etc)

59
Q

what does the nucleolus do?

A

synthesis of ribosomal rna

60
Q

what is the nucleolus?

A

spherica. structure within nucleus made of RNA, histones and enzymes

61
Q

What is an example of a cell that constantly performs phagocytosis?

A

white blood cell (phagocytes)

62
Q

what is the result of having too much water in the body?

A

hydrolysis of cells

63
Q

what are some symptoms when there is too much water in the body?

A
  • pitting oedema
  • swelling of cells
64
Q

what are some examples of molecules transported via active transport?

A
  • ions, proteins, anything that needs to be digested
65
Q

what are some examples of molecules transported via facilitated diffusion?

A

ions, glucose, amino acids

66
Q

what are some examples of molecules transported via simple diffusion?

A

lipids, gases (02, co2), h20

67
Q

does active transport require a transmembrane protein to function?

A

yes

68
Q

does facilitated diffusion occur down or against the concentration gradient?

A
  • down
69
Q

E.R., golgi apparatus, mitochondria, ribosome
which of these are not membrane bound?

A

ribosome

70
Q

what does glycoprotein do on the phospholipid bilayer?

A

use for recognition of own cell

71
Q

what does the cholesterol chain do on the phospholipid bilayer?

A

helps maintain membrane structure and allow fluidity
helps prevent extreme cell temperature

72
Q

what does channel protein do on the phospholipid bilayer?

A

allow ions/ blood proteins. stuff with wrong charge to pass through

73
Q

function of centriole

A

microtubule organising centre
aid cell division

74
Q

function of smooth er

A

processing of lipids and detoxicfication

75
Q

function of lysosome

A

site of endocytosis

76
Q

function of cytosol

A

enables diffusion of ions and acts as a homeostatic omponent

77
Q

heterochromatin

A

compressed chromatin stored inside the body

78
Q

how long does it take for differentiation of cells to occur?

A

6-8 days

79
Q

how long does it take for cells to divide?

A

24 hrs

80
Q

how are muscle cells specialised?

A

cytoskeleton of muscle cells have proteins allowing them to interact and cause contraction

81
Q

how are red blood cells specialised?

A

contains iron that can carry o2, only cell that has this function

82
Q

how big are human cells on average? (diameter

A

0.1 mm