life at cellular level 1 Flashcards

1
Q

what is a cell

A

the living unit of all things

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2
Q

why are cells so small

A

the bigger the cell, the smaller the SA:V, the smaller the exchange of gases

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3
Q

difference between prokaryotic and eukaryotic

A
prokaryotic: 
1- no membrane bound organelles
2-DNA in loops- no nucleus-no membrane
3-bacteria cells
4-no mitochondria
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4
Q

different types of stem cell

A

TOTIPOTENT; can differentiate into any cell. Difference with pluripotent is that it can give rise to embryo and placenta.
MULTIPOTENT-can differentiate into many different types of cell
PLURIPOTENT- Can differentiate into any cell

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5
Q

what is the plasma membrane made up of?

A

phospholipid bilayer- hydrophobic tail and hydrophilic heads

proteins embedded into the layer which allow the membrane to carry out a series of functions.

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6
Q

what functions does the cell-membrane have? (6)

A
1- transport
2-cell-adhesion
3-bonds to cytoskeleton and extracellular matrix
4-receptor
5-enzyme activity
6- cell to cell recognition
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7
Q

Function of bonding to cytoskeleton and extracellular matrix?

A

helps maintain the structure of the cell

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8
Q

Function of acting as a receptor?

A

Chemicals can bond to proteins embedded in the membrane. this might cause them to change shape and in turn initiate a chemical response inside the cell

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9
Q

function of acting as an enzyme?

A

proteins embedded in membrane can catalyse an activity or a whole metabolic pathway.

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10
Q

different types of transport?

A
  • facilitated diffusion- Requires concentration gradient and carrier molecules
  • diffusion-non-polar molecules which are lipophilic
  • pinocytosis: Non -specific. Small molecules move into cell in many individual vesicles
  • Receptor-mediated endocytosis
  • Phagocytosis: Specific form of pinocytosis
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11
Q

Cell death

A

Apoptosis- programmed cell death.

  • Apoptosis and cell proliferation are what control cell development.
  • Cell death can either be physiological(apoptosis) or pathological( response to an injury).
  • Physiological- membrane bleb- few hours- no damage to adjacent cell
  • Pathological- membranes rupture- days- inflammation- damage to adjacent cells-necrosis
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12
Q

Cell signalling

A
  • Paracrine- signalling cell releases local mediator to target cells
  • Endocrine- hormone released into bloodstream-binds to receptors on target cells
  • Autocrine
  • Contact-depending: depends on cell adhesion
  • Synapsing
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13
Q

Cell organelles

A

Mitochondria:
-Outer membrane: contains porin
-Inside membranes: Cristae
-own DNA and ribosomes
Nucleus:
-Nucleoli-sites of rRNA synthesis.
-Nuclear envelope closely associated with RER
-DNA, nucleoproteins,RNA
ER
-rough-has ribosomes attached, works with Golgi in production of proteins and modification of proteins
-Smooth used for assembly of lipid compounds or breakdown of certain compounds e.g. drugs
Lysosomes;
-used for autophagy-destruction of cell-self material or engulfed particles
Cytoskeleton:
-made up of microfilaments, intermediate filaments and microtubules
-holds organelles in place, helps move them

Perixosome:

  • contains catalase ( regulate hydrogen peroxide conc.)
  • contains oxidase: involved in beta-oxidation
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