All Organisms Are Made of Cells

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All Organisms Are Made of Cells

• All living things are composed of cells
• Cells are the basic unit of structure and
  function in living things
• All cells come from pre-existing cells

• The Cell Theory

2
Overview Of Animal Plants

• Organelle
• Plasma membrane

• Mini-organ
• Most are membrane bound perform specific
  functions
• Outer covering that defines the boundary
• Regulates things going in and out
• Crucial for homeostasis

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Overview of Plant Animal Cells

• Nucleus
• Cytoplasm

• Membrane bound structure that houses the DNA
• Fluid that fills entire cell and suspends the
  organelles

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Two Major Classes of Cells

• Prokaryotic Cells

• Lack a nucleus and other membrane bound
  organelles
• Bacteria
• Archaea
• Earliest cells in Earths fossil record

Cell wall
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Two Major Classes of Cells

• Eukaryotic Cells

• True nucleus
• Membrane bound organelles
• Much bigger in size

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Is It Alive?

• Viruses ?

• Some characteristics of life
• Smallest infectious agents
• Composed of mostly protein and genetic material
• Coat called capsid
• Some have envelope similar to cell membrane

Cell Size
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Structure of Cell Membrane

• Membrane Structure

• Phospholipid molecule
• Phosphate head
• Hydrophilic
• Contains arrangement of atoms attached to
  glycerol including phosphate group
• Lipid tail
• Hydrophobic
• Two fatty acid chains

Hydrophilic head (polar)
Polar Group Phosphate Glycerol
fatty acid chain
fatty acid chain
Hydrophobic tail (non-polar)
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Structure of Cell Membrane

• Organization of phospholipids

• Bilayer (2 layers)
• Hydrophobic tails make up inside layer
• Hydrophilic heads face extra-cellular space and
  intra-cellular space

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Structure of Cell Membrane

• Proteins within the membrane
• Enzymes- carry out reactions
• Facilitate communication between cells and allows
  for recognition between cells
• Assists in the transport of molecules across the
  membrane (like water sugars)

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Membranes Regulate the Traffic of Molecules

• 2 ways materials such as water, salts, sugar, and
  nutrients move across the cell membrane, in order
  to maintain homeostasis
• PASSIVE TRANSPORT

• 1. Passive transport
• 2. Active transport
• Molecules move from an area of high concentration
  to an area of low concentration
• No energy required

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Equilibrium

• Movement of molecules continues, across the
  membrane, but at the same rate in both directions
• Molecules are equally dispersed ? BALANCE

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• Simple diffusion
• Small molecules (oxygen carbon dioxide) pass
  through the membrane from an area of high
  concentration to an area of low concentration
• Facilitated diffusion
• Larger molecules use protein channels to move
  across the membrane from an area of high
  concentration to an area of low concentration

• Types of Passive Transport

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Moving Molecules against a Gradient
When molecules are moved from an area of lower
concentration to area of higher
concentration Cell expends energy Usually
performed to prevent equilibrium from occurring
Example Neuron

• Active transport

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Passive Transport Continued

• Passive transport of water across a selectively
  permeable membrane
• Water moves from an area of high concentration to
  an area of low concentration
• A solution is made up of two things Solute
  and Solvent
• Solute Substance in a solution that is dissolved
  present in a lesser amount
• Solvent Substance in a solution that dissolves
  the other substance is present in a greater
  amount

• Osmosis
• Solutions

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Types of solutions

• Hypertonic solution
• Hypotonic solution
• Isotonic solution

• Hyper over
• Hypertonic solution is a solution that has a
  high concentration of solutes
• Hypo under
• Hypotonic solution is a solution that has a low
  concentration of solutes
• Iso same
• Isotonic solutions are ones that have an equal
  concentration of solutes and water in and outside
  of the cell

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Osmosis in Different Cells
Turgor Pressure The pressure produced inside the
cell from a hypotonic solution
Plasmolysis When the cell membrane shrinks away
from the cell wall.
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Organs of the Urinary system- Chapter 32.2

• Kidneys
• Ureters
• Urinary bladder
• Urethra

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Urinary System

• Kidneys
• 2 Bean shaped structures
• Excrete waste products regulate water and salt
  balance
• Filter the blood
• Produce urine Liquid composed of water, urea,
  and other nitrogen containing waste products
• Ureters (2)
• Tubes that extend from each kidney carrying urine
  to the urinary bladder

• 4 Organs

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Urinary System

• Urinary Bladder
• Collapsible sac that temporarily holds urine
  until it is eliminated from the body
• Urethra
• Urine leaves the bladder through another tube
  called the urethra

• 4 Organs

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Urinary System

• Primary Goal of the
• Kidney

• Excrete waste products and regulate water and
  salt balance
• Two Roles
• Clean out toxins from blood
• Restore water

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4 Steps Involved when Blood is Processed Urine
is Excreted

• Step 1 Filtration
• Blood pressure forces water and small solutes,
  including urea, into the Bowmans Capsule
• Step 2 Reabsorption
• Active Transport reabsorbs
• Glucose, amino acids, and other ions from the
  filtrate back into the blood
• Water solution left behind is hypotonic causing
  osmosis to move water back into the blood

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4 Steps Involved when Blood is Processed Urine
is Excreted

• Step 3 Secretion
• The following substances are transported from the
  blood back into the filtrate
• Nitrogenous waste products
• Urea
• Uric Acid
• Toxins
• Excess Water

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4 Steps Involved when Blood is Processed Urine
is Excreted

• Step 4 Excretion
• Remaining filtrate is transported to the bladder
  to leave the body

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Regulating Water Balance

• Mechanisms of homeostasis regulate the amount of
  water reabsorbed by the kidney
• Example Negative Feedback Loop
• How the body responds to a stimulus, in order to
  create a balance again

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Regulating Water Balance

• Decrease water level in your body
• Increase concentration of solutes in your blood
• Thirst center in your brain is activated
• Motivates you to drink
• ADH (anti-diuretic hormone) is released
• ADH travels in the blood to the kidneys ?
  stimulates the nephrons to reabsorb more water
• Result
• Decrease in solute concentration in the blood to
  within the normal range
• Water content of urine decreases ? Yellow
  concentrated

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Regulating Water Balance

• Drink too much water
• Solute concentration in blood drops below the
  normal range
• Less ADH is released from the brain
• Lower level of ADH, decreases the amount of water
  reabsorbed in the nephrons
• Result
• Urine contains more water ? lighter in color

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Transporting Large Molecules

• Moving large molecules into the cell within
  vesicles
• Vesicles Small membrane bound sacs specialized
  in moving materials in and out of cell
• Moving large molecules out of the cell within
  vesicles

• Endocytosis
• Exocytosis