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

more information!

for

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:  http://www.youtube.com/watch?v=l9ymaSzcs dY&NR=1&feature=fvwp Euglena:  http://www.youtube.com/watch?v=7DALQ XLJ4Q&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:    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:  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  The 2 solutions have equal concentrations of solute and solvent.

Hypotonic solutions  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?

 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

   

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      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   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:   Mechanical work, chemical work, transport work Basically, all cellular processes ATP in cells = good for only a few seconds of activity (not efficient storage)   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  Concludes plants gain most of their mass from water Joseph Priestly  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)  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=   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: CO 2 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 higher energy 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 5 carbon molecules  These are reused in the next cycle!!!

Factors affecting photosynthesis

   Availability of Water  Shortage of water can slow or stop photosynthesis Temperature  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 (O 2 present) Anaerobic (in the absence of O 2 )

Cellular Respiration Overview

   Oxygen + glucose  carbon dioxide +water +energy 6O 2 + C 6 H 12 O 6  6CO ATP 2 + 6H 2 O + 3 main stages:    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)  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!

   Cells convert NADH back into NAD + electrons back to pyruvate by passing Allows glycolysis to continue to produce ATP (not efficient) 2 main types:  Alcoholic Fermentation (bacteria and yeast)  Lactic Acid Fermentation (humans)

Alcoholic Fermentation

    Yeasts and bacteria Beer, wine, and bread production Pyruvic acid + NADH  alcohol + CO 2 +NAD + In bread:   CO 2 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 O 2 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 CO 2 and electrons are removed forming NADH CO 2 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 FADH 2 NADH from the Kreb’s cycle   and 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 electrons with hydrogen ions and oxygen to form water  an enzyme that combines the

Energy Totals

  Aerobic Respiration = 36 ATP     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 activity  used in a few seconds of intense Then, ATP is generated via lactic acid fermentation

Energy and Exercise

 Long-term energy     (marathon) For exercise longer than 90 seconds respiration is the only way to generate enough ATP to sustain activity.

 cellular Stored energy = glycogen (breaks down into glucose and is stored in muscles)  Lasts only about 15-20 minutes Once glycogen is depleted  stores (good for weight loss!) body uses fat

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 Cell Respiration Function Location Reactants Products Equation

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 this do to the Traffic?

What does this do to the Waste and Nutrients?

What does this do to the Resources needed to thrive?

What does this do to the people who run the town?

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

 1.

2.

 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

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  original) 2 daughter cells (exact copies of the Prokaryotes  easy   Circular DNA Eukaryotes   copies then divides 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 G 0 (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 1-2 days Can divide Lining of small intestine Lining of large intestine Red blood cell White blood cell Smooth muscle Cardiac (heart) muscle Skeletal muscle Neuron (nerve cell) 6 days Less than 120 days 10 hours to decades Long-lived Long-lived Long-lived Long-lived Can divide Cannot divide Cannot divide Can divide Cannot divide Cannot divide 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.