Transcript Cells - South Kingstown High School

Cells
Cell Structure and Function
Photosynthesis
Cellular Respiration
Cell Growth and Division
Cell Structure and Function
(Chapter 7)
Life is Cellular

How did the Cell Theory develop?


Cell Theory Guided Reading activity
Know the contributions of the following
scientists:







Robert Hooke (1665)
Anton van Leeuwenhoek (1674)
Matthias Schleiden (1838)
Theodor Schwann (1839)
Rudolph Virchow (1855)
Janet Plowe (1931)
Lynn Margulis (1970)
Prokaryotes vs. Eukaryotes

Prokaryotes =

Eukaryotes=
Use my website to determine the major
differences between eukaryotes and
prokaryotes.
Cell Structures
Use the webquest on animal and plant cell
organelles and their functions as notes for
this section.
 Go to my website, click on links, then click
on “cells alive!”
 Or go to http://www.cellsalive.com for
more information!

The Compound Microscope

Review the
microscope lab
activity as notes for
this section!


Know the parts of the
microscope and be able
to accurately label a
microscope diagram!
Know how to make a
wet mount slide!
Cellular Diversity

Protists:



Webquest on
“What are
Protists?”
Protista lab
activity
Animal and Plant
Cells:

Observing Animal
and Plant Cells
lab activity
Protist Lab Video Clips

Paramecium:


Euglena:


http://www.youtube.com/watch?v=l9ymaSzcs
dY&NR=1&feature=fvwp
http://www.youtube.com/watch?v=7DALQXLJ4Q&feature=related
Amoeba:

http://www.youtube.com/watch?v=I3Jo7moaL
dI&feature=related
Levels of Organization in Multicellular
Organisms

Use the Levels of Organization webquest
as notes for this section.
20 minute research activity:
Structure and Function
Choose a cell type and research
how it’s structure helps it
function.
Cells performing the same function often are
similar in shape
Question: “How does the cell shape affect
it’s function/allow it to function?”
 Choose from one of these cell types:


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
Neuron
Red Blood Cell
Cheek Epithelial Cell
Product Ideas:

PowerPoint, Poster, graphic organizer, song,
interpretive dance, model, acrostic poem,
concept map
Neuron
Cheek Epithelial Cell
Red Blood Cell
Neuron Notes…
Cheek Epithelial Cell Notes…
Red Blood Cell Notes…
Homeostasis in the Human Body

Use the Homeostasis in the Human Body
Webquest as notes for this section.
The Cell Membrane
Structure and Function
“Fluid Mosaic Model”
The Cell Membrane



Regulates what enters and leaves
Provides protection and support
Made up of:




Phospholipids (“lipid bilayer”)
Integral and Peripheral Proteins
Carbohydrate chains (glycoproteins)
Cholesterol
Cell membrane structure
Where are they found?

Found in:



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
Nucleus
Cell membrane
Golgi apparatus
endoplasmic reticulum
lysosomes
mitochondria
(basically any
membrane bound
organelle!)
Structure

Lipid bilayer is made
of the following:

2 types of proteins:



Integral proteins
Peripheral proteins
3 types of lipids:



Membrane
Phospholipids
Membrane glycolipids
Cholesterol
Integral proteins

Transmembrane
proteins (or integral
proteins)

Amphipathic =
hydrophobic and
hydrophilic regions
Peripheral proteins

Peripheral proteins



linked at the
cytoplasmic surface
(by attachment to a
fatty acid chain)
linked at the external
cell surface (attached
by an oligosaccharide)
may be bound to other
membrane proteins
Membrane Phospholipids



These have a polar
head group and two
hydrocarbon tails
It is connected by
glycerol to two fatty
acid tails
One of the tails is a
straight chain fatty
acid (saturated). The
other has a kink in the
tail (unsaturated).
Membrane glycolipids


Glycolipids are also a
constituent of
membranes.
These components of
the membrane may be
protective, insulators,
and sites of receptor
binding.
Cholesterol



The amount of
cholesterol may vary
with the type of
membrane.
Plasma membranes
have nearly one
cholesterol per
phospholipid
molecule.
Other membranes
(like those around
bacteria) have no
cholesterol
Cholesterol (continued)

Function:



This makes the lipid bilayer less deformable
Without cholesterol (such as in a bacterium) a
cell would need a cell wall.
Also keeps the cell membrane from becoming
too stiff.
Fluid Mosaic Model

Based on what you know about the
structure and function of the cell
membrane what does the fluid mosaic
model mean?
Diffusion, Osmosis, and Active
Transport Molecular Workbench Activity

Complete this online and use your analysis
packets as additional notes.

We will be completing this in class!
Movement Through the Membrane

Materials can move through the
membrane by:

Diffusion



Osmosis
Facilitated Diffusion
Active Transport



Protein Pumps
Endocytosis
Exocytosis
NO ENERGY (ATP)
REQUIRED
[high]  [low]
ENERGY (ATP)
REQUIRED
[low]  [high]
Diffusion
Requires no energy (ATP)
 Moves from an area of High concentration
 low concentration until dynamic
equilibrium is reached.
 Dynamic equilibrium activity
 http://www.stolaf.edu/people/giannini/flas
hanimat/transport/diffusion.swf

Osmosis
A type of diffusion (no energy needed)
 Allows water molecules to pass easily
through the selectively permeable
membrane.
 Solution = solute + solvent



Solute = sugar (or another dissolved
substance)…CANNOT go through the
membrane
Solvent = water…CAN go through the
membrane
Osmosis
ONLY water moves
 The solute stays put on one side or the
other
 Water moves back and forth according to
the concentration of water on each side of
the membrane
 http://www.stolaf.edu/people/giannini/flas
hanimat/transport/osmosis.swf

Osmotic Pressure

Isotonic solutions


Hypotonic solutions


The 2 solutions have equal concentrations of
solute and solvent.
One solution has less solute and more water
compared to the other solution.
Hypertonic solutions

One solution has more solute and less water
compared to the other solution.
What would happen?

What would happen if…

You placed a selectively permeable membrane
“bag” with a hypotonic solution into a beaker
with a hypertonic solution?

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
Which way would the water flow?
What would happen to the bag?
What would happen to the beaker?
How do you know?
How could you test this?
Facilitated Diffusion
Diffusion with the help of transport
proteins
 No energy required
 http://www.stolaf.edu/people/giannini/flas
hanimat/transport/channel.swf

Active Transport


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
Cell uses energy
Actively moves molecules to where they
are needed
Movement from an area of low
concentration to an area of high
concentration
3 MAIN TYPES:
1.
2.
3.
Protein pumps
Endocytosis (BULK TRANSPORT)
Exocytosis (BULK TRANSPORT)
Types of Active Transport
1. Protein Pumps -transport proteins that
require energy to do work



Example: Sodium / Potassium Pumps are
important in nerve responses.
http://www.stolaf.edu/people/giannini/flashani
mat/transport/secondary%20active%20transp
ort.swf
Protein changes shape to move molecules: this
requires energy!
Types of Active Transport
2. Endocytosis: taking bulky material into
a cell
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Uses energy
Cell membrane in-folds around food particle
“cell eating”
Forms food vacuole & digests food
This is how white blood cells eat bacteria!
Types of Active Transport
3. Exocytosis: Forces material out of cell
in bulk
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membrane surrounding the material fuses
with cell membrane
Cell changes shape – requires energy
EX: Hormones or wastes released from cell
http://www.stolaf.edu/people/giannini/flashani
mat/cellstructures/phagocitosis.swf
Photosynthesis
Energy and Life
Energy = ability to do work
 Source of energy on Earth = sun
 Autotrophs  use light energy from the
sun (or other sources) to make food.
 Heterotrophs obtain energy from foods
consumed.
 Energy comes in many forms


Light, heat, and electricity
ATP  “like a fully charged battery”

One of the principle chemical compounds
that is used to store energy

Adenosine triphosphate (ATP)
ADP  “like a ½ charged battery”

When energy is released from ATP 
converts to ADP and a phosphate group
Using Biochemical Energy

Cells use this energy for:
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Mechanical work, chemical work, transport
work
Basically, all cellular processes
ATP in cells = good for only a few seconds
of activity (not efficient storage)

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1 molecule of glucose stores more than 90x’s
the chemical energy of ATP
Cells can generate ATP as needed from the
glucose in carbohydrates consumed during
feeding
Investigating Photosynthesis

Jan van Helmont


Joseph Priestly


Concludes plants gain most of their mass from
water
Concludes that plants release a substance that
keeps a candle burning (oxygen)
Jan Ingenhousz

Concludes that plants produce oxygen bubbles
in the light but not in the dark (they need
sunlight).
Photosynthesis Equation
Light and Pigments
Photosynthesis requires:
 Light


From sunlight (A mixture of different wavelengths of
light)
Chlorophyll (a pigment found in chloroplasts that
absorbs light energy)

2 main types:


Chlorophyll a (absorbs violet and red light)
Chlorophyll b (absorbs blue and red light)
Structure of a Chloroplast
NADPH
When sunlight hits chlorophyll a double
bond is broken releasing a high energy
electron.
 This high energy electron requires a
special carrier called NADP+.
 Once the electron is combined with
NADP+ it becomes NADPH.
 NADPH carries this energy to other
reactions around the cell.

Light-Dependent Reactions
Use energy from sunlight to produce
Oxygen, ATP and NADPH.
 Photosystem II is the first to absorb light

(discovered after photosystem I)
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Light smashes high energy electrons out of the
chlorophyll molecules which are carried to electron
transport chains in the thylakoid membrane.
The lost electrons from the chlorophyll molecule are
replaced by breaking water molecules apart which
releases oxygen.
Light-Dependent Reactions (Continued)

High energy electrons move from
Photosystem II to photosystem I.

Energy from this transport pumps H+ ions
from the stroma into the inner thylakoid.
Pigments in photosystem I use sunlight to
release additional high energy electrons
and a H+ ion  becomes NADPH
 Inside of thylakoid membrane becomes
positively charged (from the H+
ions)/outside  negatively charged


Charge difference allows ATP to be made.
Light-Dependent Reactions (Continued)

ATP formation=

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H+ ions move through a protein called ATP
synthase.
As it rotates the protein binds ADP with an
additional phosphate to create ATP!
The Calvin Cycle:
OR the light-independent reactions



ATP and NADPH from the light reactions are
required to produce high-energy sugars.
Step 1: CO2 enters the cycle and is combined
with 6 5-Carbon molecules forms 12 3-Carbon
molecules
Step 2: Energy from ATP and NADPH are used to
convert the 12 3-Carbon molecules into higherenergy forms
The Calvin Cycle:
OR the light-independent reactions
Step 3: 2 3-Carbon molecules are used to
make a 6-Carbon sugar (glucose!)
 Step 4: The 10 remaining 3-Carbon
molecules are converted back into 6 5carbon molecules


These are reused in the next cycle!!!
Factors affecting photosynthesis

Availability of Water


Temperature


Shortage of water can slow or stop photosynthesis
Plants function best between 0°C and 35°C
(temperatures above or below may damage enzymes
and slow or stop photosynthesis)
Intensity of light

Increasing intensity increases rate of photosynthesis
until maximum rate of photosynthesis is reached.
Photosynthesis Molecular Workbench

We will be completing this online
together…Use your analysis packets as
additional notes.

We will be completing this in class!
Cellular Respiration
Chemical Pathways

Energy in food:



Calorie = amount of energy needed to raise
the temp. of 1 g of water 1°C
Gradually release energy from glucose and
other food compounds
2 Pathway for energy release


Aerobic (O2 present)
Anaerobic (in the absence of O2)
Cellular Respiration Overview
Oxygen + glucose  carbon dioxide
+water +energy
 6O2 + C6H12O6  6CO2+ 6H2O +
ATP
 3 main stages:


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
Glycolysis
The Krebs cycle (or “citric acid cycle”)
Electron Transport Chain (or “oxidative
phosphorylation”)
Glycolysis (glyco- = sweet; lysis =
breaking)



Occurs in the cytoplasm near the mitochondion
No oxygen is required for glycolysis
1 molecule of glucose (6C) is broken into 2
molecules of pyruvic acid (3C) (pyruvate)

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
Needs to use 2 ATP to get started
Generates 4 ATP at the end
Net ATP total = 2 ATP
Produces 4 molecules of NADH (high energy
electron carrier)  transports to other reaction
sites
What happens if there is no oxygen?

Fermentation!
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Cells convert NADH back into NAD+ by passing
electrons back to pyruvate
Allows glycolysis to continue to produce ATP
(not efficient)
2 main types:
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
Alcoholic Fermentation (bacteria and yeast)
Lactic Acid Fermentation (humans)
Alcoholic Fermentation
Yeasts and bacteria
 Beer, wine, and bread production
 Pyruvic acid + NADH  alcohol +
CO2 +NAD+
 In bread:



CO2 makes the bread rise
Alcohol is baked off
Lactic Acid Fermentation

Pyruvic acid is converted to lactic acid

This regenerates NAD+ so glycolysis can
continue to generate ATP
Pyruvic acid + NADH  lactic acid +
NAD+
 Produced in the muscles when there is not
enough O2 causing burning/pain


Example: Wall sit of death
What if there is oxygen present after
glycolysis?
Krebs cycle and electron transport chain!!!
 Most powerful electron acceptor =
oxygen!!!
 Uses the remaining 90% of energy still
trapped in the glucose molecule after
glycolysis!

The Krebs Cycle

Step # 1:




Pyruvic acid enters the mitochodrion
A carbon is removed forming CO2 and
electrons are removed forming NADH
CO2 is combined with coenzyme A and is
transformed into acetyl-CoA
Acetyl-CoA adds a 2-C acetyl group to a 4C
compound forming citric acid.
The Krebs Cycle (continued)

Step # 2:
 Citric acid is broken down into a 5C compound
then a 4C compound
 2 molecules of CO2 are released, electrons
form NADH and FADH2, and 1 ATP is
generated
 From one molecule of pyruvic acid=


4 NADH, 1 FADH2, 1 ATP
But remember 2 molecules of pyruvic acid are made
from each molecule of glucose!!! (so this process
happens twice)
Electron Transport

The high energy electrons in FADH2 and
NADH from the Kreb’s cycle



Are transported to the inner membrane of the
mitochondrion
In prokaryotes  ETC is in the cell membrane
The ETC uses the high energy electrons to
make ATP
Electron Transport (continued)

High energy electrons are passed to a series of
carrier proteins in the membrane



As electrons move to each carrier, H+ ions are moved to
the inner membrane space
These will be used later to generate ATP via ATP
synthase
At the end  an enzyme that combines the
electrons with hydrogen ions and oxygen to form
water
Energy Totals

Aerobic Respiration = 36 ATP

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
Uses 38% of the total energy of a molecule of
glucose
The rest is released as heat (body heat!)
More efficient than a gasoline car engine
We are an efficient combustion engine!!!
Anaerobic Respiration = 2 ATP
Energy and Exercise

Quick energy  (a sprint)



ATP is short-lived and is used right away
Stored ATP  used in a few seconds of intense
activity
Then, ATP is generated via lactic acid
fermentation
Energy and Exercise

Long-term energy  (marathon)



For exercise longer than 90 seconds  cellular
respiration is the only way to generate enough
ATP to sustain activity.
Stored energy = glycogen (breaks down into
glucose and is stored in muscles)
 Lasts only about 15-20 minutes
Once glycogen is depleted  body uses fat
stores (good for weight loss!)
Linking to Homeostasis

Rate of Cellular Respiration Inquiry (RITES
lab using BIOPACS)



Heart Rate Monitor
Design an experiment to test the rate of
cellular respiration
How does cellular respiration work to
maintain homeostasis in the human body?

Include body systems in your response.
Comparing Cellular Respiration to
Photosynthesis

Generate a chart comparing the following:
Photosynthesis
Function
Location
Reactants
Products
Equation
Cell Respiration
Cellular Respiration Molecular
Workbench

Complete this online and use your analysis
packets as additional notes.


We will be completing this in class!
TedX talk –Discovering ancient
climates in oceans and ice: Rob
Dunbar on TED.com
Cell Growth and Division
Limits to Cell Size Activity

Draw an example of a town with the
borders being the edges of the paper


There is one main road into and out of the
town.
Think of a cell and the parts needed to run the
cell.
 Recreate these parts as parts of a town
 Don’t forget: nutrients (food trucks) and
waste (dump trucks)
Limits to Cell Size Activity
Increase the Population by THREE TIMES
 What does this do to the demands put on
the town?:





What does
What does
What does
thrive?
What does
town?
this do to the Traffic?
this do to the Waste and Nutrients?
this do to the Resources needed to
this do to the people who run the
Limits to Cell Size Activity

Based on the activity…
 What are the 2 limits to cell size?
 What happens when a cell becomes
too big?
Cell Growth
2 limits to cell size =
The larger the cell becomes the more demands
the cell places on its DNA
The cell has difficulty moving nutrients and
waste across the membrane
Thus the size of a cell is limited

1.
2.


As the length of a cell increases…

Volume increases faster than its surface area
What happens when a cell gets too big?
IT DIVIDES!!!
 Cell division




1 cell  2 daughter cells (exact copies of the
original)
Prokaryotes  easy
 Circular DNA  copies then divides
Eukaryotes  more involved
 Complex DNA (23 pairs of chromosomes =
46 total)
The Cell Cycle

Average
time =
16 – 20
hours
G1 Phase

Cell Growth



Intense growth and activity
Increases in size
Synthesizes new proteins and organelles
The Cell Cycle
S Phase

DNA Synthesis


Creates a duplicate set of chromosomes
G0 (or R on diagram) = Point of no return
Chromosome Structure
“supercoils”
Human Chromosomes (Karyotype)
The Cell Cycle
G2 Phase

Preparation for Mitosis


Shortest of the 3 phases of interphase (G1, S,
and Gs)
Organelles and proteins needed for cell division
are produced.
The Cell Cycle
Mitosis
Prophase
 Metaphase
 Anaphase
 Telophase
 Cytokinesis

Prophase



Chromosomes condense (“appear”)
Nuclear envelope dissolves
Centrioles move to opposite sides (poles) of
the cell
Metaphase


Centrioles send out spindle fibers that attach to
the chromosomes
Chromosomes are lined up in the middle of the
cell
Anaphase

Chromosomes (sister chromatids) are
pulled apart and move to the poles.
Telophase/Cytokinesis
Occurs simultaneously
 Telophase




The nuclear envelope reforms around the
chromosomes
The chromosomes uncoil
Cytokinesis


The cytoplasm divides
2 daughter cells are produced (each are exact
copies of the original with 46 chromosomes)
What stages are these cells in?
Investigating Cell Reproduction

Complete the lab activity

Paper lab
GO TO Meiosis PowerPoint
Regulating the Cell Cycle
Controls on Cell Division
Cell growth and division can be turned on
and off
 Example



Cells in a petri dish will continue to grow until
they come in contact with other cells.
A cut in the skin will cause cells to divide until
the wound in healed.
Cell Cycle Regulators

Cyclin



Protein that regulates the cell cycle in
eukaryotic cells
When injected into a non-dividing cell it causes
a mitotic spindle to form
Internal Regulators


Responds to events inside the cell
Makes sure that a cell does not enter mitosis
until all chromosomes are replicated
Cell Cycle Regulators (cont.)

External Regulators


Respond to events outside the cell
“Growth factors” that speed up or slow down
growth and division
Uncontrolled Cell Growth

CANCER –


Cells that lose the ability to control cell growth
Most cancers have damage to the p53 gene




Normally halts the cell cycle until all chromosomes
are replicated
Chromosome damage builds up and the cancer cell
loses the information that controls normal cell growth
Tumors  masses of cells that can damage the
surrounding tissue
CAUSES: smoking tobacco, radiation exposure
(UV, XRAY, etc.), viral infection
Life Spans of Various Human Cells
Cell Type
Life Span
Cell Division
Lining of esophagus
2-3 days
Can divide
Lining of small
intestine
1-2 days
Can divide
Lining of large
intestine
6 days
Can divide
Red blood cell
Less than 120 days
Cannot divide
White blood cell
10 hours to decades
Cannot divide
Smooth muscle
Long-lived
Can divide
Cardiac (heart)
muscle
Long-lived
Cannot divide
Skeletal muscle
Long-lived
Cannot divide
Neuron (nerve cell)
Long-lived
Most do not divide
Life Spans of Human Cell Questions


White blood cells help protect the body from
infection and disease-producing organisms. How
might their function relate to their life span?
If cancer cells were added to the table, predict
what would be written under the “Life Span” and
“Cell Division” columns. Explain you’re the
reasoning behind your predictions.