CHAPTER 3: CELLS

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1

vesicular transport

transport of large particles/macromolecules across plasma membranes

2

exocytosis

moves substances from the cell interior to the extracellular space

3

endocytosis

enables large particles/macromolecules to enter the cell

4

phagocytosis

  • pseudopods engulf solids
  • bring solids into cell's interior
5

resting membrane potential

  • potential energy due to separate charges
  • voltage different across the membrane
  • range -20 to -200 mV
6

roles of membrane receptors

  1. contact signaling
  2. electrical signaling
  3. chemical signaling
7

membrane receptor: contact signaling

where cells come in contact

*important in normal development and immunity

8

membrane receptor: electrical signaling

voltage regulated "ion gates" in nerve/muscle tissue

9

membrane receptor: chemical signaling

nerotransmitters bind to chemically gated channel-linked receptors in nerve/muscle tissue

10

cytoplasm

material between plasma membrane/nucleus

11

cytosol

largely water with dissolved protein, salts, sugars and other solutes

12

cytoplasmic organelles

metabolic machinery of the cell

13

inclusions

storage of chemical substances

14

membranous organelles

specialized cellular compartments defined by membranes

15

membranous organelles: peroxisomes

detoxification

16

membranous organelles: lysosomes

clean up crew/recycling facility

17

membranous organelles: endoplasmic reticulum

  1. rough
  2. smooth
18

membranous organelles: rough endoplasmic reticulum

rough due to ribosomes

19

membranous organelles: smooth endoplasmic reticulum

lipid metabolism

20

membranous organelles: Golgi apparatus

shipping/packaging protein

21

non-membranous organelles: cytoskeleton

  • the "skeleton" of the cell
  • consists of: microtubules/microfilaments/intermediate filaments
22

non-membranous organelles: centrioles

  • located in the centrosome near the nucleus
  • made of microtubules
  • form the bases of cilia/flagella
23

motor molecules

  • powered by ATP
  • protein complexes
  • attach to receptors
24

cilia

  • move substances in one direction across cell surfaces
  • useful to clean surfaces such as respiratory walls
25

nucleus

  • contain genes (the "blueprints" of the organism)
  • control center of the cell
  • houses: nuclear envelope/nucleoli/chromatin
26

chromatin

threadlike strands of DNA/structural protein

when nucleus divides, chromatin condenses to form chromosomes

27

cell division

essential for body growth/repair

  1. mitosis
  2. cytokinesis
28

mitosis

nuclear divison

4 phases:

  1. prophase
  2. metaphase
  3. anaphase
  4. telophase
29

cytokinesis

division of the cytoplasm

30

mitosis: prophase

...

31

mitosis: metaphase

...

32

mitosis: anaphase

...

33

mitosis: telophase

...

34

cell cycle

  1. interphase
  2. mitotic
35

DNA replication

  • helices untwists the DNA double helix into 2 nucleotide chains
  • appears as a replication bubble
  • services as a template for semiconservative replication
36

protein synthesis

...

37

transcription

  • transfer of information from DNA to mRNA
  • mRNA is synthesized
38

translation

  • occurs in the cytoplasm @ the ribosomes
  • involves all types of RNA; mRNA, tRNA, rRNA
  • translation of DNA into polypeptide amino acid sequence
39

3 types of RNA

  1. messenger
  2. transfer
  3. ribosomal
40

messenger RNA

carries the genetic information from DNA in the nucleus to the ribosomes in the cytoplasm

41

transfer RNA

brings amino acids to the ribosomes according to the codons of mRNA

42

ribosomal RNA

a structural component of ribosomes

43

info transfer from DNA to RNA

  • DNA triplets are transcribed into mRNA codons by RNA polymerase
  • codons base pair with tRNA anticodons at the ribosomes
  • amino acids are peptide bonded at the ribosomes to form polypeptide chains
  • start/stop codons are used in initiating/ending translation
44

extracellular materials

body fluids/cellular secretions

45

plasma membrane

  • separates fluids inside the cell (intracellular) from fluids outside the cell (extracellular)
  • important in cellular activities
46

fluid mosaic model

  • double bilayer of lipids with proteins interspersed throughout
  • bilayer consists phospholipids, cholesterol, glycolipids
47

fluid mosaic model: glycolipids

lipids with carbohydrates attached

48

fluid mosaic model: phospholipids

have hydrophobic and hydrophilic ends

49

functions of membrane proteins

  1. transport
  2. enzymatic activity
  3. receptors for signals
50

membrane junctions

  1. tight
  2. desmosome
  3. gap
51

membrane junctions: tight

impermeable junction that encircles the cell

EX) glue

52

membrane junctions: desmosome

junctions scattered along the sides of the cells

EX) staples

53

membrane junctions: gap

allows chemical substances to pass between cells

54

passive membrane transport: diffusion

substances move from an area of high concentration to an area of low concentration (DOWN the concentration gradient)

55

passive membrane transport: simple diffusion

  • non polar and lipid - soluble substances
  • diffuse directly across the lipid bilayer
56

passive membrane transport: facilitated diffusion

large polar molecules, diffused across with the "help" of special protein carriers

EX) simple sugars

57

active transport

  • moves substances against their concentration gradients (from LOW to HIGH)
  • requires energy to do this; uses ATP to move solutes across the membrane
  • requires special carrier proteins (gates/pumps)
58

active transport: secondary

use of an exchange pump indirectly to drive the transport of the other solutes

59

tonicity: isotonic

solutions with the same solute concentration as that of the cell interior

60

tonicity: hypertonic

solutions having GREATER solute concentration (less water) than the cell interior

61

tonicity: hypotonic

solutions having LESSER solute concentration (more water) than the cell interior

62

passive membrane trasport: osmosis

occurs when the concentration of a solvent is different on opposite sides of a membrane

63

osmosis

diffusion of water across a semipermeable membrane

64

osmolarity

  • total concentration of sole particles in a solution
  • water flows down concentration gradient (more water/fewer solutes) to area (less water/more solutes)