All Organisms Are Made of Cells

The Cell Theory

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

Overview Of Animal & Plants

Organelle

Plasma membrane

“Mini-organ”Most are membrane bound

& perform specific functionsOuter covering that defines

the boundaryRegulates things going in

and outCrucial for homeostasis

Overview of Plant & Animal Cells

Nucleus

Cytoplasm

Membrane bound structure that houses the DNA

Fluid that fills entire cell and suspends the organelles

Two Major Classes of Cells

Prokaryotic Cells Lack a nucleus and other membrane bound organellesBacteriaArchaeaEarliest cells in Earth’s

fossil record

Cell wall

Two Major Classes of Cells

Eukaryotic Cells True nucleusMembrane bound

organellesMuch bigger in size

Is It Alive?

Viruses ? Some characteristics of life

Smallest infectious agents

Composed of mostly protein and genetic material

Coat called capsidSome have envelope

similar to cell membrane

Cell Size

Structure of Cell Membrane

Membrane Structure Phospholipid molecule

Phosphate head HydrophilicContains arrangement

of atoms attached to glycerol including phosphate group

Lipid tailHydrophobicTwo fatty acid chains

Polar Group

Phosphate

Glycerol

Hydrophilic head (polar)

fatt

y a

cid c

hain

fatt

y a

cid c

hain

Hydrophobic tail (non-polar)

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

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)

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

Equilibrium

Movement of molecules continues, across the membrane, but at the same rate in both directions

Molecules are equally dispersed BALANCE

Types of Passive Transport

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 http://www.biology.com/

Moving Molecules against a Gradient

ACTIVE TRANSPORT

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

Passive Transport Continued

Osmosis

Solutions

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

Types of solutions

Hypertonic solution

Hypotonic solution

Isotonic solution

Hyper = overHypertonic solution is a solution that has a high concentration of solutes

• Hypo= underHypotonic solution is a solution that has a low concentration of solutes

• Iso= sameIsotonic solutions are ones that have an equal concentration of solutes and water in and outside of the cell

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.

Organs of the Urinary system- Organs of the Urinary system- Chapter 32.2Chapter 32.2

Kidneys

Ureters

Urinary bladder

Urethra

Urinary System

4 Organs Kidneys

2 Bean shaped structuresExcrete waste products & regulate

water and salt balanceFilter 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

Urinary System

4 Organs Urinary Bladder

Collapsible sac that temporarily holds urine until it is eliminated from the body

UrethraUrine leaves the bladder through

another tube called the urethra

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

4 Steps Involved when Blood is Processed & Urine is Excreted

Step #1 = FiltrationBlood pressure forces water and small solutes,

including urea, into the Bowman’s Capsule

Step #2 = ReabsorptionActive 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

4 Steps Involved when Blood is Processed & Urine is Excreted

Step #3: SecretionThe following substances are transported from

the blood back into the filtrateNitrogenous waste products

• Urea• Uric Acid• Toxins

Excess Water

4 Steps Involved when Blood is Processed & Urine is Excreted

Step #4: ExcretionRemaining filtrate is transported to the bladder

to leave the body

Regulating Water Balance

Mechanisms of homeostasis regulate the amount of water reabsorbed by the kidneyExample: Negative Feedback Loop

How the body responds to a stimulus, in order to create a balance again…

Regulating Water BalanceDecrease water level in your body

Increase concentration of solutes in your bloodThirst center in your brain is activated

Motivates you to drinkADH (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 rangeWater content of urine decreases Yellow; concentrated

Regulating Water Balance

Drink too much waterSolute concentration in blood drops below the

normal rangeLess ADH is released from the brainLower level of ADH, decreases the amount of

water reabsorbed in the nephronsResult:

Urine contains more water lighter in color

Transporting Large MoleculesEndocytosis

Exocytosis

Moving large molecules into the cell within vesicles

Vesicles: Small membrane bound sacs specialized in moving materials in and out of cell

o Moving large molecules out of the cell within vesicles