Download Chapter 3 PPT 3 - Blair Community Schools

9/30/16
Golgi Apparatus
Cells:
The Living Units
Chapter 3, PPT 2
Membrane
•  Yes, stacked and flattened
Description
•  Stacked and flattened membranous sacs
Function
•  Modify, concentrate, and package proteins
& lipids made at Rough ER
•  Traffic director / post office
Golgi Apparatus
Special Details
•  Release secretory vesicles
Lysosomes
Membrane
•  Yes
Description
•  Spherical bags containing digestive enzymes
Lysosomes
Function
•  Digest particles taken in by endocytosis (bacteria,
viruses, and toxins)
•  Degrade worn out and nonfunctional organelles
and tissues
•  Perform metabolic functions
•  Break down bone to release calcium ions
Lysosomes
Special Details
•  Large and abundant in phagocytes
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Peroxisomes
Membrane
•  Yes
Description
•  Spherical bags containing powerful digestive enzymes
(Oxidases and peroxidases)
Function
•  Neutralize dangerous free radicals
–  Oxidase converts them to H2O2 (hydrogen peroxide)
–  Peroxidases catalyze H2O2 à H2O + O2
What are the three elements of the cytoplasm?
1.  Cytosol
2.  Cytoplasmic Organelles
3.  Inclusions
What is cytosol?
Viscous fluid in which the other elements are
suspended
What is an inclusion
Chemical substances that may or may not be present,
depending on the cell
Which organelles are nonmembranous?
Cytoskeleton, centrioles, ribosomes
How many membranes does mitochondria have?
Two
What is Cristae
Folds of inner membrane in mitochondria
What is matrix?
Gel-like substance in the inner portion of
mitochondria
What does it mean if a cell has a lot of
mitochondria?
It needs a lot of energy
What is the formula for cellular respiration?
C6H12O6 + 6O2 à 6CO2 + 6H2O + ATP
What organelle synthesizes (makes) protein?
Ribosomes
Where are ribosomes for that cell made?
In free floating ribosomes
Where are ribosomes for other cells made?
On the rough ER
What do we call the extensive system of interconnected
tubes and parallel membranes enclosing fluid-filled
cavities?
The Endoplasmic Reticulum
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What special feature do you find in the membrane of
smooth ER?
Integral Enzymes
What do they do?
Catalyze reactions
Name two functions of the smooth ER:
–  Lipid metabolism, absorption, transport
–  Cholesterol & sex hormone synthesis
–  Detox of drugs, pesticides and carcinogens
–  Breakdown of stored glycogen to free glucose
What two things are synthesized in the rough ER?
Proteins and lipids
What is the function of the Golgi Apparatus?
Modify, concentrate, and package proteins
& lipids made at Rough ER
What is a secretory vesicle?
A membranous sac that is released to be
secreted
Do lysosomes and perxisomes have membranes?
Yes
What are the membranes made of?
Phospholipid bilayer
In one word, what does a lysosome do?
Digest
In one word, what does a peroxisome do?
Neutralize
In two words, what does a mitochondria do?
Make ATP / energy
In three words, what does the Golgi do?
Package, modify, transport
Endomembrane System
•  System of organelles that work together
Structure
ER
Lysosomes
Golgi Apparatus
Nuclear envelope
Secretory vesicles
Function
•  Produce, store, and export biological molecules
•  Degrade potentially harmful substances
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Endomembrane System
Cytoskeleton
•  System of organelles
that work together
“Cell skeleton”
Structure
– 
– 
– 
– 
– 
Three types of rods (no membranes)
1) Microtubules
2) Intermediate Filaments
3) Microfilaments
ER
Golgi Apparatus
Secretory vesicles
Lysosomes
Nuclear envelope
Function
•  Produce, store, and
export biological
molecules
•  Degrade potentially
harmful substances
Figure 3.23
Microtubules
• 
• 
• 
• 
Size: Largest diameter
Composition: Hollow tubes, tubulin subunits
Radiate from a centrosome region
Function: Determine overall shape of cell,
distribution of organelles (polymerization and
depolymerization)
Microfilaments
Size: Thinnest elements
Composition: Actin
Function:
•  Strengthen cell surface
•  Membrane changes of endocytosis and
exocytosis
Intermediate Filaments
Size: Intermediate
Composition: Tough, insoluble protein fibers
Function:
•  Internal guy-wires to resist pulling motions on
cell
Cytoskeleton
Wonder of the Cell Video
•  Motor proteins walking on microtubules
–  @ 28:43-29:45
•  Cytoskeleton & microtubules
–  @ 38:25-42:01
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Centrosome
•  Microtubule organizing
center
•  Microtubules anchored near
nucleus
•  Contains paired centrioles
–  Small barrel-shaped
organelles oriented at right
angles to form mitotic
spindle
Cellular Extensions
Cilia
Flagella
•  Whip-like, motile cellular
extensions
•  Occur in large numbers on
exposed surfaces of certain
cells
•  Move substances in one
direction across cell surfaces
•  Long singular cilia
•  Propels cell itself
Nucleus
•  Control center of cell
•  Genetic Library
–  Contains all instructions to build body’s proteins
–  Dictates kinds and amounts of proteins to be
synthesized
THE NUCLEUS
Nucleus #s
•  One nucleus
–  Most cells
•  Multinucleate
–  Skeletal muscle cells
–  Bone destruction cells
–  Some liver cells
Nucleus
Three structures/regions
1. Nuclear envelope
2. Nucleoli
3. Chromatin
•  Anucleate
–  Mature red blood cells
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Nuclear Envelope
Nucleoli
•  Double membrane barrier separated by fluid
filled space
•  Outer membrane continuous with rough ER
•  Nuclear pores - areas where 2 membranes fuse
•  Selectively permeable
•  Contains nucleoplasm
•  Where ribosome subunits are assembled
•  Usually 1 or 2 per nucleus
•  Contain DNA that issues genetic instructions
for synthesizing ribosomal RNA (rRNA)
–  Like cytoplasm/cytosol
Chromatin
•  Structure
–  30% DNA
–  60% Histone Protein
•  Compact the DNA
•  Gene regulation
–  10% RNA
•  Function
–  Form chromosomes when cell is
ready to divide
CELL GROWTH AND
REPRODUCTION
Figure 3.29
Cell Life Cycle
•  Series of changes a cell goes through from the
time it is formed until it reproduces
•  2 major phases
– Interphase
Interphase
•  Period from cell formation to cell division
–  Metabolic phase
–  Growth phase
•  Cell growth
•  Regular functions
– Mitotic phase
•  Cell division
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Subphases of Interphase
Subphases of Interphase
S (synthetic) phase
•  DNA replication
•  New histone proteins formed
G1 (gap 1)
•  Cell is metabolically active
•  Synthesizing proteins
•  Rapid growth
•  Can take minutes to years
–  What did histones do?
G0
•  Phase of cells that permanently cease dividing
Mitotic Phase - Cell Division
G2 (gap 2)
•  Final, brief phase of interphase
•  Enzymes, proteins, and organelles are
replicated
DNA Replication
•  DNA helix begins to unwind
•  Helicase enzyme untwists double helix and
separates DNA into two chains (exposes
nucleotides)
•  Free nucleotides serve as a template for a new
strand
•  New DNA segments spliced together by DNA
ligase
•  Essential for body growth and tissue repair
•  Two parts
– Mitosis
•  nuclear division
– Cytokinesis
•  division of the cytoplasm
DNA
Replication
Cell Division - Preview
Figure 3.31
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Prophase
Mitosis
•  Distinct pairs of chromosomes become
apparent (tightly coiled DNA and protein)
•  Each pair of chromosomes is made of identical
sister chromatids, held together by a
centromere
•  Pairs of centrioles migrate to opposite ends of
the cell, form spindle fibers between them
•  Nuclear envelope and nucleolus disappear
•  4 Phases
–  Prophase
–  Metaphase
–  Anaphase
–  Telophase
Early & Late Prophase
Metaphase
•  Chromosomes line up
midway between centrioles
•  Centromere holding each
pair of chromosomes
together attaches to spindle
fiber between centrioles
Figure 3.32.2
Anaphase
•  Centromere holding
chromosome pair together
separates
•  Individual chromosomes
migrate in opposite directions
on the spindle fibers toward
polar centrioles
•  Cytokinesis begins
Telophase
•  Chromosomes complete
migration toward centrioles
•  Nuclear envelopes develop
around each set of
chromosomes
•  Nucleoli develop
•  Spindle fibers disappear
•  Cleavage furrow nearly
complete
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Cytokinesis
•  Division of the cytoplasm
•  Contractile ring causes plasma
membrane to draw inward
and form a cleavage furrow
•  Furrow deepens until it
pinches into two daughter
cells
•  Each daughter cell is smaller
and has less cytoplasm than
mother cell but is genetically
identical
Protein Synthesis
•  Gene
–  Segment of DNA that carries instructions for creating one
protein
–  Nucleotide bases are “letters” of DNA (A, G, T, C)
•  Triplet/Codons - sequence of 3 bases that form
“words” or amino acids
•  tRNA - transfer RNA
•  rRNA - ribosomal RNA
•  mRNA - messenger RNA
Protein Synthesis Preview
Transcription
•  Transfer of information
from a DNA gene’s
base sequence to the
complementary base
sequence of an mRNA
molecule
•  Codon - 3-base
sequence of mRNA
Translation
•  Language of nucleic
acids is translated
into the language
of proteins
•  Anticodon - 3-base
sequence of tRNA
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