biol 121 chp 3 pt2: cell structure and function
TRANSCRIPT
1
The Cellular Level of
Organiza3on Part 2: Cell Structure & Func3on
BIOL 121: A&P I
Chapter 3
Rob Swatski Associate Professor of Biology
HACC – York Campus Text
book
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es -
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yrig
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201
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ed.
Flagellum Chroma.n
Nuclear pore
Nuclear envelope
Nucleolus
Glycogen granules
CYTOPLASM (cytosol plus organelles except the nucleus)
Rough endoplasmic re.culum (ER)
Membrane-‐bound ribosome
Golgi complex
Microfilament
Sec.onal view
Cytoskeleton:
Microtubule
Microfilament
Intermediate filament
Microvilli
Centrosome: Pericentriolar material
Centrioles
PLASMA MEMBRANE
Secretory vesicle
Lysosome
Smooth endoplasmic re.culum (ER)
Peroxisome
Mitochondrion
Microtubule
Cilium
Proteasome
Free ribosomes
NUCLEUS:
Cytoplasm
Cytosol
Water Solutes Macro-‐
molecules
Cyto-‐skeleton
Protein filaments
Organelles
Membrane-‐bound
3
4
Cytoskeleton
Cytoskeleton
Microfilaments
Intermediate filaments
Microtubules
5
Func3ons of the Cytoskeleton
Support & strength
Maintains cell shape
Organizes metabolic reac.ons
Moves organelles & cell
6
7
Microfilaments
Ac.n
Support cell
Movement
Microfilaments
8
Intermediate Filaments
Kera.n
Support cell
Anchor organelles
9
Intermediate Filaments 10
Intermediate Filaments (Kera3n)
11
Microtubules
Tubulin
Cell shape
Transport organelles
Separate chromosomes
12
Microtubules 13
Centrosomes
14
Centrosomes
Contain centrioles
MT-‐organizing centers
Create mito3c spindle
15
TEM
Pericentriolar material
65,000x Centrioles
Longitudinal sec/ons
Transverse sec/on
Centrioles
Centrioles
17
Mito3c spindle
18
Cilia
Many
Short
Sweep materials across cell
Flagella
Single
Long
Move en.re sperm cell
19
20 Cilia
Flagellae 21
22
Sperm with flagellum
Sperm fer3lizing egg (oocyte) 23
24
Microtubules in Cilia & Flagella
9+2
25
Cell surface
Power stroke
Recovery stroke
Cilium
Movement of liquid
1
2 3
4
5
6 7
8
Ciliary Movement
Cell surface
Movement of cell
Flagellar Movement
Ribosomes Endoplasmic re.culum
Golgi complex Lysosomes
Peroxisomes Mitochondria
Organelles
28
Ribosomes
Proteins & rRNA
Made by nucleolus
Small & large subunits
Sites of protein synthesis
29
Endoplasmic Re3culum
Tube-‐like membrane network
Rough ER
Smooth ER
30
ER
31
Golgi Complex
Stack of flat membrane sacs
Receives transport vesicles
Processes, sorts, packages, &
delivers proteins 32
Entry face cisterna
Medial cisterna
Exit face cisterna
Transport vesicle (to lysosome)
Proteins in membrane vesicle merge with plasma membrane
Proteins exported from cell by exocytosis
Plasma membrane
Membrane vesicle
Rough ER Ribosome
Synthesized protein Transport vesicle
Transfer vesicle
Secretory vesicle
Transfer vesicle
1
2
3
5
4
6
4
7
8
9
Golgi complex
Lysosomes
Membrane-‐bound vesicles
Cellular “stomachs”
Contain diges.ve enzymes
34
Func3ons of Lysosomes
Phagosome
Autophagy
Apoptosis (Autolysis)
35
Peroxisomes
Smaller membrane-‐
bound vesicles
Contain enzymes that oxidize
organic wastes
Break down facy acids, amino acids, toxins
36
Mitochondria
Outer & inner membrane (cristae)
Matrix
Aerobic cellular respira3on (makes ATP)
37
TEM 80,000x
(b) Transverse sec.on
Outer mitochondrial membrane
Inner mitochondrial membrane
Mitochondrial matrix
Mitochondrial cristae
Mitochondrial Myopathy 39
Nucleus
Nuclear envelope with
pores
Nucleolus
DNA
Chroma3n & chromosomes
40
(a) Details of the nucleus
Nuclear envelope
Nuclear pore
Nuclear envelope Nuclear pore
Polyribosome
Chroma.n Nucleolus
Rough endoplasmic re.culum
(b) Details of the nuclear envelope
DNA
Chroma3n
Non-‐dividing cells
Unorganized, loose threads
Chromosomes
Dividing cells Genes
42
43
Chroma3n
Chromosomes
SEM 6050x
Chroma.ds
Centromere
Chromosome
Chromosomes
Chromosomes & loci 45
46
DNA Condensa3on
47
Protein Synthesis
Transcrip3on
Transla3on
48
Step 1: Transcrip3on
49
50
51
Step 2: Transla3on
(a) Components of a ribosome and their rela.onship to mRNA and protein during transla.on
(b) Interior view of tRNA binding sites
mRNA
Large subunit
Protein
Small subunit
mRNA binding site
P site A site E site
Ribosomes: Large & Small Subunits
Ini.ator tRNA acaches to a start codon.
Amino acid (methionine)
An.codon
Ini.ator tRNA
mRNA
Small subunit
Start codon
Key: = Adenine = Guanine = Cytosine = Uracil
1
1. Ini3a3on
Large and small ribosomal subunits join to form a func.onal ribosome and ini.ator tRNA fits into P site.
Ini.ator tRNA
Large subunit
E site
Small subunit
P site
A site
2
Key: = Adenine = Guanine = Cytosine = Uracil
An.codon of incoming tRNA pairs with next mRNA codon at A site.
tRNA
An.codon
Amino acid
mRNA Codons
3
Key: = Adenine = Guanine = Cytosine = Uracil
Amino acid on tRNA at P site forms a pep.de bond with amino acid at A site.
4
Key: = Adenine = Guanine = Cytosine = Uracil
The two-‐pep.de protein created from the forma.on of the pep.de bond becomes acached to tRNA at A site.
New pep.de bond
5
Key: = Adenine = Guanine = Cytosine = Uracil
Ribosome shihs by one codon: tRNA previously at P site enters E site and is released from ribosome; tRNA previously at A site is now at P site.
6
Key: = Adenine = Guanine = Cytosine = Uracil
Protein synthesis stops when the ribosome reaches stop codon on mRNA.
7
Stop codon
Key: = Adenine = Guanine = Cytosine = Uracil
mRNA Growing protein
Complete protein
Summary of movement of ribosome along mRNA
Key: = Adenine = Guanine = Cytosine = Uracil
Nucleus
DNA
Nuclear pore
RNA
Plasma membrane
Cytoplasm
RNA
Ribosome
Protein
Step 1: Transcrip3on
Step 2: Transla3on
Cell Division
Soma3c
Body cells Mitosis & Cytokinesis
Reproduc3ve
Sperm & Eggs
Meiosis & Cytokinesis
62
S
G2
M
G1
Cell Cycle
63
S phase DNA replicated
(8 hours)
G2 phase Cell growth con.nues; enzymes and other
proteins are synthesized; centrosome replica.on completed.
G1 phase Cell metabolically ac.ve; duplicates organelles and
cytosolic components; centrosome replica.on begins.
G0 Exit from cell
cycle (nondividing cell) An
aphase
Metaphase
INTERPHASE
8-‐10 hou
rs 4-‐6 hours
MITOTIC (M) PHASE
65
S-‐phase: DNA Replica3on
66
Mito3c Phase
67
Interphase
Nucleus & nucleoli intact
DNA = Chroma3n
Cell is not dividing
68
69
Interphase
Prophase
Metaphase
Anaphase
Telophase
70
71
Prophase Nucleus & nucleoli
disappear
Centrosomes move to opposite poles
Chroma.n à Chromosomes
Chroma3ds & centromere
72
73
Prophase
Spindle Made by
centrosomes
Microtubule spindle fibers
Binds to centromeres
Asters
74
Spindle asters
75
Centrosomal protein muta3on
76
Metaphase Centromeres @ metaphase plate
Alignment & symmetry @ poles
Prepara.on for separa.on
77
78
Metaphase
Metaphase
79
Anaphase Spindle fibers disassemble
Centromeres split & chroma.ds separate
Daughter chromosomes move to opposite poles
80
81
Anaphase
Anaphase
82
Telophase Reverse of Prophase
Chromosomes à Chroma.n
Spindle disassembles
Nucleus & nucleoli re-‐
form 83
84
Telophase
Cytokinesis
Cytoplasmic division
Cleavage furrow
Completed aher nuclear
division
85
86
Cytokinesis
87
Meiosis Reproduc.ve cell division
Produces gametes
(sperm & eggs)
Diploid (2n) à Haploid (n)
Two stages: Meiosis I & Meiosis II
88
Centrioles
PROPHASE I
Centromere
Chromosome
Tetrad
Sister chroma.ds
Tetrads formed by synapsis of sister chroma.ds of homo-‐logous chromosomes
METAPHASE I Cleavage furrow
Separa.on of homologous chromosomes ANAPHASE I
TELOPHASE I
Metaphase plate
Pairing of homologous chromosomes
Crossing-‐over between nonsister chroma.ds
Kinetochore microtubule
Meiosis I
Prophase I
90
Crossing-‐over
91
Meiosis I, cont.
92
93
Meiosis II
MEIOSIS II MEIOSIS I
TELOPHASE I PROPHASE II
METAPHASE II
ANAPHASE II
TELOPHASE II Meiosis Overview
95
96
Mitosis vs. Meiosis
PROPHASE I
PROPHASE
MEIOSIS MITOSIS Star.ng cell
2n Chromosomes
already replicated
Tetrads formed by synapsis
Crossing-‐over
METAPHASE I Tetrads line up along the metaphase plate
ANAPHASE I
Each cell has one of the replicated chromosomes from each homologous pair of chromosomes (n)
Homologous chromosomes separate (sister chroma.ds remain together) TELOPHASE I
PROPHASE II
PROPHASE PROPHASE II
METAPHASE II
ANAPHASE II
TELOPHASE II
METAPHASE
ANAPHASE
TELOPHASE
INTERPHASE
2n 2n
Chromosomes line up along the metaphase plate
Sister chroma.ds separate
Cytokinesis
Resul.ng cells
n n n n
Soma.c cells with diploid number of chromosomes (not replicated)
Gametes with haploid number of chromosomes (not replicated)