Cells (Chapter 2) Flashcards

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1
Q

Cell theory

A
  • All living organisms are composed of one or more cells.
  • The cell is the basic unit of structure and organization in organisms.
  • Cells arise from pre-existing cells
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2
Q

Endoplasmic reticulum

A
  • Provide a surface on which chemical reactions can occur
  • The channels between the paired membranes are used for storage and transport of materials
  • Rough endoplasmic reticulum has ribosomes attached to it
  • Smooth endoplasmic reticulum has no ribosomes
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3
Q

Ribosomes

A
  • Site of protein synthesis
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4
Q

Lysosomes

A
  • Small spheres that contain enzymes able to break down proteins, lipids, nucleic acids
  • Formed from golgi body
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5
Q

Vesicle

A

membrane-bound sac that transports materials into, out of, or within the cell

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6
Q

Nucleus

A

Contains the genetic material of a cell

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7
Q

Mitochondria

A
  • Where cellular respiration takes place (energy production)
  • The folding of its inner membrane produces a large surface area for these chemical reactions to take place
  • Called ‘powerhouses’ of cell
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8
Q

Golgi body

A
  • Modifies and packages proteins for their secretion from the cell
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9
Q

Why do cells prefer a high surface area to volume ratio?

A

Becasue if the volume of a cell is too big compared to the surface area the cell can’t exchange material efficiently enough to stay alive.

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10
Q

Homeostasis

A

The maintenance of the balanced environment a cell needs to operate

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11
Q

Phospholipid bilayer

A
  • The basic ‘part’ of the cell membrane
  • Phospholipids contain a head and a tail
  • The head contains a phosphate group and likes water (hydrophilic)
  • The tail is made of lipids (fats) and dislikes water (hydrophobic)
  • Contains carrier proteins which act as a tunnel for substances to move in and out at will
  • Contains channel proteins which bind to a particular substance to carry them through the membrane in and out of the cell
  • Contains cholesterol molecules which sit within the bilayer, acting as velcro the keep the phospolipids joined
  • Also cell identity markers which are nametags for the cell, letting the immune system know that the cell is not a foreign invader
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12
Q

Functions of the cell membrane

A
  • Physical barrier between cytoplasm and extracellular fluid
  • Regulation of passage of materials
  • Support
  • Sensitivity - uses receptors to detect changes in the environment
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13
Q

Transport across membrane

A

The membrane is selectively permeable. Permeable meaning it allows liquids and gases to pass through and selectively referring to having control over what goes in and out. There are 3 basic forms of transporting material across the membrane:
Diffusion
Carrier-mediated transport
Vesicular transport

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14
Q

Diffusion

A
  • The movement of small molecules such as oxygen and carbon dioxide directly across the cell membrane along a concentration gradient (from areas of high concentration to low concentration)
  • The greater the differential between high and low the steeper the concentration gradient. The steeper the concentration gradient the quicker diffusion happens.
  • A passive process
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15
Q

Osmosis

A

the diffusion of a water from high to low concentration through a selectively permeable membrane in order to balance the concentration of another substance.

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16
Q

Two types of carrier-mediated transport

A
  • Facilitated diffusion:
    Passive (doesn’t require ATP)
    Moves with the concentration gradient
  • Active transport:
    Active (requires ATP)
    Moves against the concentration gradient
17
Q

Endocytosis and Exocytosis

A
  • Endocytosis – entering the cell. The cell membrane engulfs the solid or liquid until it’s completely enclosed. The vesicle is then engulfed in the cytoplasm.
  • When the cell engulfs solids it is called phagocytosis. When it engulfs liquids it is called pinocytosis.
  • Exocytosis - exiting the cell. A vesicle is formed around contents in the cytoplasm, and migrates to the membrane. It then fuses with the membrane and pushes the contents outside.
18
Q

4 types of tissues

A
  • Muscular, contains muscle fibres which contract becoming shorter to contract the muscle
  • Epithelial, lines body surfaces, cavities, glands, cells close together
  • Connective, provides support and structure, cells separated by material called matrix
  • Nervous, composed of neurons that receive and transmit information around the body as electrical impulses
19
Q

3 types of muscle tissue

A
  • Skeletal muscle
    -Muscles that are attached to our skeleton.
    -Striated appearance
    -Controlled voluntarily.
  • Smooth / Involuntary muscle
    -Muscles that make up our organs.
    -No striations so referred to as smooth or non-striated
    -Can not be controlled voluntarily
  • Cardiac muscle
    -Muscle of the heart.
    -Faint striations.
    -Can not be controlled voluntarily.