Cellular Level Of Organization Flashcards

1
Q

What is the cell?

A
  • basic structural and functional unit of the body
    • can perform all basic life functions
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2
Q

What are the principal parts of the cell?

A
  1. Cell Membrane/Plasma Membrane/Plasmalemma
  2. Cytoplasm
  3. Nucleus
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3
Q

Cell Membrane/Plasma Membrane/Plasmalemma

A
  • Boundary between the inside and outside of a cell.
  • Composed of:
    1. Phospholipid belayer
    2. Cholesterol
    3. Membrane Proteins
    4. Membrane Carbohydrates
    5. Microvilli
      1 & 3. Fluid Mosaic Model
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4
Q

Phospholipid Bilayer

A
  • phosphate head group (HYDROPHILIC -> loves water)
  • FA tails (HYDROPHOBIC -> hates water)
  • divides ICF and ECF
    • Intracellular Fluid (ICF) = Inside cell
    • Extracellular Fluid (ECF) = outside cell
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5
Q

Cholesterol

A
  • Scattered throughout membrane
  • Adds stability to the cell membrane
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6
Q

Membrane Proteins

A
  • 2 types:
    • integral protein
    • peripheral protein
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7
Q

What are the functions of membrane proteins?

A
  • enzymes
  • transporters
  • channels
  • receptors
  • anchors
  • identity markers (for immune system
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8
Q

What is integral proteins?

A
  • integrated within the membrane, therefore, have a hydrophobic region
  • some extend across entire membrane, and are called transmembrane proteins
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9
Q

What is peripheral proteins?

A
  • attached to either surface of integral proteins I.e. on the periphery of the cell membrane
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10
Q

Membrane Carbohydrate

A
  • only on outer surface
  • bound to protein (glycoproteins) or lipids (glycolipids)
  • Function:
    • cell recognition e.g. sperm recognize egg cell
    • anchor cells together
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11
Q

Microvilli

A
  • small projections of cell membrane
  • function is to increase surface area ( helps absorb nutrients)
  • best seen on cells of the small intestine and kidney
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12
Q

Fluid Mosaic Model of the Cell Membrane

A
  • fluid = membrane constituents can move around (phospholipids and some proteins)
  • Mosaic = proteins dot surface like tiles in a mosaic
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13
Q

What is the Cytoplasm?

A
  • AREA between the inside of the cell membrane and the outside of the nucleus
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14
Q

What are the 2 divisions of Cytoplasm?

A
  1. Cytosol = gel-like intracellular fluid
  2. Organelles
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15
Q

What is Cytosol?

A
  • Contains water, ions, and a suspension of carbohydrates, proteins, and lipids
  • May contain inclusions e.g. Melanin (pigment, glycogen (stored glucose)
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16
Q

What is Organelles?

A
  • Structures that perform a specific function and are essential for life
  • are either:
    • Non-membranous (in direct contact with cytosol)
    • Membranous (surrounded by membrane that isolates them from cytosol)
17
Q

What are non -membranous organelles?

A
  1. Ribosomes
  2. Centrosomes
  3. Cytoskeleton
18
Q

Ribosomes

A
  • Sites for protein synthesis
  • Contains ribosomal (rRNA) and proteins
19
Q

What Two Types Can Ribosome Be?

A
  1. Free ribosomes - float in cytosol and make proteins that go to cytosol, mitochondria, and/or nucleus
  2. Attached to endoplasmic Reticulum (ER) - make proteins destined for all other sites
20
Q

Centrosomes

A
  • Consist of 2 components: a pair of centrioles and the pericentriolar matrix
  • Organizing centres for microtubules
    • Spindle apparatus (for cell division)
    • Organizes cytoskeleton
21
Q

Cytoskeleton

A
  • All types are for structural support (for cell shape) and are formed from proteins
  • important in cell movement, cell division, movement/anchoring of organelles and proteins (e.g. receptors, enzymes)
22
Q

What are the 3 types of Cytoskeleton?

A
  1. Microfilaments
  2. Intermediate Filaments
  3. Microtubules
23
Q

what is Microfilaments and it’s function?

A
  • Made of actin
  • Function: Muscle contraction (with myosin), cell locomotion and cytokinesis
24
Q

Intermediate Filaments

A

Composition is tissue specific
- e.g. Keratin

25
Q

what is Microtubules and it’s function?

A
  • Hollow tubes made of tubulin
  • Function:
    • Form:
      • Centrioles
      • Spindle Apparatus
      • Cilia (short)
      • Flagella (long)
    • Move or secure organelles in place
26
Q

What are Membranous organelles?

A
  1. Mitochondria
  2. Endoplasmic Reticulum (ER)
  3. Golgi Apparatus/Complex
  4. Lysosomes
27
Q

Mitochondria

A
  • Site of ATP synthesis
  • Contains own DNA, RNA, and proteins
  • have a double membrane
28
Q

Endoplasmic Reticulum (ER)

A
  • Membranous network throughout cytoplasm
  • 2 types:
    1. Rough ER (RER)
    2. Smooth ER (SER)
29
Q

Rough ER (RER)

A
  • Ribosomes attached - synthesis of secretory, lysosomal and membrane proteins
30
Q

Smooth ER (SER)

A
  • Lacks attached ribosomes
  • Continuous with RER
  • Synthesizes lipids and steroid hormones
31
Q

Golgi Apparatus/Complex

A
  • Stacks of membrane discs
  • modifies proteins (e.g. trims or adds carbs and lipids), sorts, packages, and delivers them to cell membrane, lysosomes, or for secretion (cellular post office))
32
Q

Lysosomes

A
  • Filled with digestive enzymes
  • Digest bacteria, viruses, worn-out organelles (clean up function)
33
Q

What is the Nucleus?

A
  • Largest membranous organelle
  • cell control centre
  • cells may have 1 or more nuclei
34
Q

What are the 3 parts of the nucleus?

A
  1. nuclear envelope
  2. Nucleolus (>1 in some plants)
  3. Chromosomes/chromatids
35
Q

Nuclear Envelope

A
  • Double membrane with nuclear pores
  • Connected to ER
36
Q

Nucleolus (>1 in some plants)

A
  • Non-membranous
  • Dense (less light gets through) region of DNA, RNA, and proteins where ribosomes are made and assembled
37
Q

Chromosomes/Chromatids

A
  • Contain DNA and histone proteins
  • Can be:
    1. Dispersed = Chromatin
      • DNA uncoiled and not individually visible
      • In this form most of the time (when cell is not dividing)
    2. Condensed and individually visible
      • Found in dividing cells (during mitosis/meiosis)