Chap 3 - Cells
Learning Objectives:
1. Describe the structure and function of
the major cell organelles.
2. List the phases of the cell cycle and
describe the key events in each phase.
3. Describe DNA replication.
Homework: Read Chapter 3, pgs 78 – 91 (Beginning with “The
Cytoplasm” through “Chromatin”). Review Table 3.3, “Parts of the
Cell: Structure and Function” pgs 88 – 89.
OPENING ACTIVITY
CSI: Solving Crimes with DNA Evidence
http://www.cbs.com/primetime/csi_miami/
Goal: To learn more about how DNA is used in crime-scene
investigation
Instructions:
∙ Work in a group of 5-6 people.
∙ Quickly review the CSI case (there are 3 identical
copies enclosed – share amongst yourselves).
∙ Use the CSI resource cards in the packet to help you
formulate answers to the 5 questions on the first page
(left-hand side) of the case. Try to formulate answers in
your own words (re-state) rather than copying word-forword.
∙ Be prepared to share and discuss your conclusions
with the class.
Follow-Up Discussion
1. What is DNA?
2. What kinds of cells is DNA typically
isolated from?
3. How is DNA tested for a possible match?
Site at least 2 different types of tests and
explain what they reveal.
4. What does “epithelials” refer to?
5. When a cell no longer has a nucleus, how
can DNA be extracted form that cell?
PREDICT
How many cells in your body?
How many different kinds?
Typical Cell Structure, page 60
Instructions: Individually,
practice labeling the
organelles on the handout.
The Plasma
Membrane
Plasma membrane
• Surrounds the entire cell
• Made of phospholipids and
___________
• Is __________ permeable (it
allows some substances to pass
through but not others)
• Substances move through the
membrane _________ (not
requiring any energy as in
diffusion and filtration) or
__________ (requiring energy
form ATP)
Question: What is ATP? (*homework from Ch 2)
The Cytoplasm
• The _______ _______ between the plasma
membrane and the nucleus
• Gelatin-like
• Consists of organelles – helps everything
hang together
Nucleus
• ______ _______ of the cell
• Larger than most other cell
organelles
• Most cells have one nucleus but some are
multinucleated
• 3 recognizable regions:
1. nuclear _________ (a double semipermeable membrane surrounding the nucleus)
2. _________ (dark spherical area on the
nucleus where ribosome subunits are assembled)
3. _________ (DNA containing area; when a cell
is preparing to divide, the chromatin coils and
condenses to form short chromosomes.)
Mitochondria
• ______ _______ of the cell
providing ATP
• Contain both ____ and ____
• Sausage-shaped membranous
organelles
• In living cells they squirm,
elongate, and change shape
• Consists of 2 membranes (an
outer and an inner membrane
called the _______ which folds
back and forth upon itself)
Ribosomes
• Small, dark-stained granules of ______
and a type of RNA called ________ RNA
• Sites of _______ synthesis
Endoplasmic Reticulum (ER)
• A network within the cytoplasm (interconnected
tubes and membranes enclosing fluid-filled cavities
or cisternae)
• Continuous with the nuclear membrane
• There are 2 types:
1. ___________ (no part in protein synthesis –
they help with lipid metabolism, steriod-making
hormones, detox of drugs, breakdown of stored
glycogen)
2. ________ (studded with ribosomes which
produce all proteins secreted form cells)
Golgi Apparatus
• Principle ‘traffic director’ for cellular
_______
• Main function is to modify, concentrate,
and package the ______ and ______
made at the rough ER
Lysosomes
• Spherical organelles containing _________
enzymes
• Digest _______, viruses, and toxins
• Degrade worn out or nonfunctional __________
• Perform glycogen breakdown and release
• Breakdown nonuseful tissues such as the webs
between the developing fingers/toes of a fetus
• Break down ______ to release Ca+ into the
blood
Peroxisomes
• Contain powerful enzymes like _________
(molecular O2 to detox harmful alcohols
and formaldehyde). Also, neutralize
dangerous free radicals.
Cytoskeleton
(NOTE: Visible only when the cell is getting ready
to _________)
• Centrioles – small, barrell-shaped
organelles oriented at right angles to one
another
Cellular Extensions
• Cilia – ________ motile extensions
• Flagella – ________ undulating motile
extensions
Review
• Which organelle is the command center of
the cell and contains chromatin?
Which organelle contains oxidases to
detox harmful substance?
Review Continued
• Organelle that contains digestive juices?
Organelle that supplies ATP?
The Cell Cycle
_______ – cell carries out all routine
functions; resting from dividing
a. ______ (G_) – growth phase;
several minutes to hours in
length
b. _________ (S) - DNA is
replicated
c. ________ (G_) – growth and
final preparations for division
Mitotic phase – series of events
that parcel out the replicated DNA of
the original (mother cell) into two
new cells (________ cells)
Cytokinesis – ________ __ of the
cytoplasm during late mitosis
Centrioles appear
A Closer Look at DNA
Replication (S phase)
Before a cell can divide, its
DNA must be _________
so that identical copies of
the cell’s genes can be
passed on to each of its
offspring
1. Helix _______
2. 2 complimentary strands
are in place exposing the
_________ _____
3. Each strand serves as a
template
DNA Replication
Instructions: Complete the two new strands
of DNA.
Lagging Strand
Leading Strand
A-
C-
1. ?
2. ?
T-
5. ?
-T
6. ?
3. ?
7. ?
G-
-G
-A
4. ?
8. ?
-C
A Closer Look at Mitosis
http://www.cellsalive.com/mitosis.htm
Interphase (Before Mitosis)
• Cell carrying out ________ activities
• In late Interphase, ________ condenses
and two pairs of _______ appear
• The nuclear membrane also begins to
disintegrate
Nucleoli
disappear
also
Early and Late Prophase
•Asters are
seen
• Chromatin
condenses into
chromosomes
•Chromosomes
connected at
midpoint
(kinetochore)
by centromere
Centrioles
separate
from one
another;
spindle
fibers form
between
them
Metaphase
• Chromosomes cluster at the
______ of the cell with
centromeres precisely at
center/ equator of spindle
An enzyme called separase triggers
separation of the chromosomes
Anaphase
• Chromosomes are _____ ____ (now
called _________ )
• Moving chromatids look V-shaped
Telophase and Cytokinesis
• __ new cells forming
• Nucleus begins to _____ with new nuclear
envelope, nucleolus, etc.
• _________ (pinching-in of cytoplasm)
completes the division of the cell into 2
_______ cells
Review of the Mitosis
1. ?
4. ?
2. ?
3. ?
Abnormal Cell Cycles
Can result in _______ formation (cells
growing and dividing much faster than
normal)
Click to see:
http://hcd2.bupa.co.uk/fact_sheets/html/ski
n_cancer.html