Chapters 4,5,9, & 6

Front 1

Cell

Back 1

Life's basic unit of structure and function

Front 2

Plasma Membrane

Back 2

Living boundary of the cell, phospholipid bilayer

Front 3

Nucleus/Nucleoid

Back 3

Where genetic material (DNA) is stored

Front 4

Cytoplasm

Back 4

a semifluid substance that fills the rest of the cell. May contain organelles.

Front 5

Organelles

Back 5

Specialized membrane-bound compartments that preform specific functions

Front 6

Robert Hooke

Back 6

The first man to view and name "cells" in 1665

Front 7

Antonie von Leeuwenhoek

Back 7

He was the first man to observe microscopic life (300x)

Front 8

Schieiden & Schwann (1839)

Back 8

These men put forth part of what is now called the Cell theory of life

Front 9

Cell theory of life

Back 9

• All organisms are composed of cells
• The cell is life's basic unit of structure and function
• All cells come from cells

Front 10

Two types of cells

Back 10

1. Prokaryotic cells
2. Eukaryotic cells

(Both are small and measured in microns)

Front 11

Prokaryotic Cells

Back 11

• (The bacteria & cynobacteria = K. Monera)
• small- (1-10 microns),
• have a nuceoid with one circular chromosome, -Have a few simple structures but no organelles.

Front 12

Eukaryotic Cells

Back 12

• (All other kingdoms)
• Larger (10-100 microns)
• More complex; highly compartmentalized
• organelles
• true nucleus
• genetic material enclosed by a membrane & more DNA

Front 13

Nucleus

Back 13

Surrounded by nuclear envelope, with nuclear pores. Contains genetic material in the form of chromosomes (each has one molecule of DNA and proteins called histones)

Front 14

Chromatin

Back 14

Thread like form of chromosomes

Front 15

Nucleolus

Back 15

Darkened area in nucleus. Site of ribosomes.

Primary role is the synthesis of carbohydrates and lipids.

Front 16

Endoplasmic Reticulum (ER)

Back 16

Extensive membrane labyrinth throughout the cytoplasm - 2 Regions

Front 17

Rough ER

Back 17

• Ribosomes attached to cytoplasmic side
• involved in processing , temporary storing, and packing proteins

Front 18

Smooth ER

Back 18

• Lacks attached ribosomes
• Primary role is the synthesis of carbohydrates and lipids

Front 19

Glogi Apparatus

Back 19

Collects, packages, modifies and distributes products of the ER via transport vesicles

Front 20

Lysosomes

Back 20

Membrane sacs full of digestive enzymes

Front 21

Microbodies

Back 21

1. Glyoxysomes
2. Peroxisomes

Front 22

Glyoxysomes

Back 22

Convert lipids to carbohydrates in lipid rich seeds

Front 23

Peroxisomes

Back 23

Breakdown fatty acids, amino acids & hydrogen peroxide

Front 24

Ribosomes

Back 24

• Sites of protein synthesis
• Composed of ribosomes RNA & proteins
• Manufactured in the nucleus, the shipped out to the cytoplasm
• Can be free or bound

Front 25

Mitochondria

Back 25

• ("Power house of the cell")
• Involved in energy conversions
• Have DNA and ribosomes

Front 26

Plastids

Back 26

Family of plant organelles

• Chloroplast
• Amyloplast
• Chromoplast
• Central Vacuole

Front 27

Chloroplast

Back 27

• Site of protein synthesis
• Has Chlorophyll, DNA & Ribosomes

Front 28

Amyloplast

Back 28

Storage of starch

Front 29

Chromoplast

Back 29

Storage of pigments

Front 30

Central Vacuole

Back 30

Storage of water, enzymes, toxins, some pigments, etc.

Front 31

Centrioles

Back 31

Only in the cells of animals and some protists, 9 + 0 arrangement of microtubules

Front 32

Cytoskeleton

Back 32

• Meshwork of protein fibers throughout the cytoplasm.
• Gives structure, anchors organelles, and allow cell movement.
• composed of three fibers: Actin, Microtubules & Intermediate Filaments.

Front 33

(Organelles of Movement)

Cilia

Back 33

• Short hair-like structures
• Usually occur in great numbers & beat together

Front 34

(Organelles of Movement)

Flagella

Back 34

• Similar to cilia
• Longer and more whip like
• Usually only one or two per cell

Front 35

What do Cili and Flagella have in common?

Back 35

• They both have the same internal structure
• 9 + 2 arrangement of microtubules

Front 36

(Organelles of Movement)

Basal Bodies

Back 36

• Anchor cilia & flagella just below the cell surface
• Identical in structure to a centriole ( 9 + 0 arrangement of microtubules)

Front 37

Many membrane-bound vesicle types of structures probably arose as in pocketings of cell membrane that pinched off and became specialized in some type of function.

Back 37

Roger that

Front 38

Theory of Endosymbiosis

Back 38

May explain how mitochondria & chloroplasts arose

Front 39

What is the Plasma Membrane?

Back 39

The living barrier of the cell

Front 40

The Basic Structure to a Phospholipid Bilayer

Back 40

A sheet of lipids only two molecules thick

Front 41

They spontaneously arrange themselves this way due to hydrophobic interactions

(phospholipid bilayers)

Back 41

This is simply the most stable arrangement

Front 42

Three major types of membrane lipids:

Back 42

1. Phospholipids
2. Glycolipids
3. Steriods

Front 43

Phospholipids

Back 43

Most common. Fatty acid tails can be saturated or unsaturated

Front 44

Glycolipids

Back 44

Similar to phospholipids, but have a sugar chain attached to the phospholipid

Front 45

Steroids

Back 45

Made of 4 fused carbon rings. Most common one in animals is cholesterol.

Front 46

Membranes are very fluid

Back 46

The membrane lipids can move freely about within the plane of the membrane.

Front 47

To remain fluid at lower temps. , the cell can:

Back 47

1. Replace saturated fatty acids with unsaturated ones (the kinks in the tails prevents them from packing together closely)
2. Insert cholesterol (for animals) into the phospholipid bilayer. (such bulky molecules prevent phospholipids from packing together.

Front 48

The lipid bilayer forms the basic framework for the membrane, but most of the membrane's functions are carried out by membrane proteins that float on or in the lipid bilayer.

Back 48

Great.

Front 49

Membrane Proteins

Back 49

1. Transport Proteins (channel proteins and carrier of proteins bind specific substances.)
2. Enzymes
3. Receptor Proteins (bind substances that trigger altercations in a cells metabolism or behavior.)
4. Cell Surface Identity Markers(identify he cell to other cells)
5. Cell Adhesion Proteins (Help cells attach to other cells)
6. Linking Proteins (anchor many proteins to the carbohydrates)

Front 50

The Fluid Mosaic Model

Back 50

The currently accepted model of membrane structure (proposed by Singer & Nicolson in 1972)

Front 51

What do lipid bilayers form?

Back 51

The basic structure of the membrane

Front 52

Proteins associate with the membrane

Back 52

• Transmembrane, or Integral, proteins that extend all the way through the membrane
• Peripheral proteins associated with one side of the membrane or the other.

Front 53

Sugar chains are often bound to proteins (glycoproteins) and lipids (glycolipids) in the membrane, but always on the external side of the membrane.

Back 53

They serve as distinctive identity markers (for example, in blood types). This "sugar coating" seen outside the cell is call the glycocalyx

Front 54

The plasma membrane is selectively permeable - depends primarily on

Back 54

1. Size- small uncharged molecules cross easily
2. Polarity- large polar molecules cross with difficulty (but non polar still cross easily)
3. Electrical Charge- rejected without the help of a transport protein

Front 55

Passive Transport

Back 55

Transport across the membrane, uses no energy, goes from high to low

1. Simple Diffusion
2. Facilitated Diffusion
3. Osmosis

Front 56

Simple Diffusion

Back 56

The net movement of substances from areas of higher concentration to lower concentration

Front 57

The Rate, or Speed of diffusion depends largely on:

Back 57

• The steepness of the concentration gradient (in cress steepness --> increase rate)
• The temperature ( increase temp. --> decrease rate)
• Molecular size ( increase size --> increase rate)

Front 58

Facilitated Diffusion

Back 58

Movement of a substance across the membrane using a specific carrier protein

Front 59

Osmosis

Back 59

Diffusion of water across a selective permeable membrane

Front 60

Solution

Back 60

Consists of solute (substance being dissolved) and solvent (substance used to dissolve solutes)

Front 61

When comparing the solute concentrations of to solutions there are a few terms that are useful:

Back 61

1. Isosmotic (isotonic) - solution concentrations of two solutions are the same
2. Hypoosmotic (hypotonic) - the solution with the lesser solute concentrate
3. Hyperosmotic (hypertonic) - the solution with the greater solution concentrate

Front 62

In hypotonic solution...

Back 62

an isolated animal cell (like a blood cell) could swell to the point of bursting.

Front 63

A cell with a rigid cell wall, (like a plant cell)

Back 63

would swell as far as the cell wall would allow, it would have the mechanical support of the wall to keep it from bursting.

Front 64

If the cell is place in a hyper osmotic fluid, the opposite would occur

Back 64

the cell would lose water and shrink

Front 65

When placed in an isosmotic environment

Back 65

a cell will stay the same

Front 66

Active Transport

Back 66

• The cell uses energy to pump substances across the membrane,
• can go against their concentration or electrochemical gradients.
• It involves highly specific membrane transport proteins that act as pumps

Front 67

There are several types of membrane transport proteins:

Back 67

1. Uniport
2. Coport

Front 68

Uniport

Back 68

Transports one substance at a time

Front 69

Coport

Back 69

Transports two substances at a time

• Symport- substances moved in same direction (co-transport)
• Antiport- two substances moved in opposite directions(counter-transport)

Front 70

Bulk Transport

Back 70

• Endocytosis
• Exocytosis

Front 71

Endocytosis

Back 71

Substances brought into the cell, 3 types : Phagocytosis,Pinocytosis, Receptor

Front 72

Phagocytosis

Back 72

"Cell Eating", the uptake of solid or particulate matter into phagocytotic vesicles

Front 73

Pinocytosis

Back 73

"Cell Drinking" the uptake of liquid material from the cell surroundings

Front 74

Receptor

Back 74

Mediated Endocytosis - receptor proteins on the plasma membrane bind specifically to substances and transport them into the cell. The receptors are located in pits coated with the protein clathrin ("coated pits"), pinches off to become a "coated vesicle"

Front 75

Exocytosis

Back 75

Reverse of endocytosis, discharges materials from vesicles at the cell surface

Front 76

Energy is the capacity to do work

Back 76

Flows one way through life from the sun

Front 77

Redox Reactions

Back 77

An electron is taken from one molecule or atom (oxidized) and donated to another (reduced)

Front 78

First Law of Thermodynamics

Back 78

• Energy content of the universe is constant
• Energy cannot be created or destroyed, but can convert from one form to another

Front 79

Second Law of Thermodynamics

Back 79

• Disorder is the universe increases with every energy conservation.
• Entropy (a measure of the disorder of a system) increases

Front 80

Free Energy (G)

Back 80

The amount of energy available to do work in a system

Front 81

Two types of reactions with regard to energy:

Back 81

1. Endergonic
2. Exergonic

Front 82

Endergonic

Back 82

Net gain of free energy (+NET G), products are more complex & contain more energy than reactants, "uphill reactions"

Front 83

Exergonic

Back 83

Net release of free energy (-NET G), products are simpler & contain less energy than the reactants, spontaneous, "downhill reactions"

Front 84

Active Energy

Back 84

The energy it takes to break the bonds in a molecule so that its atoms can be rearranged

Front 85

Catalysts

Back 85

Speed up reactions. Enzymes are globular proteins that catalyze virtually all reactions in the cell

Front 86

Enzyme Characteristics

Back 86

1. Speed up reactions that would occur anyway by millions of times
2. Not permanently altered or used by the reaction
3. Each reacts with only very specific substrates
4. Lower the activation energy of reaction

-physically stress bonds with "induced fit

-hold substrates in proper orientation for reaction

-provide ideal microenvironment for reaction

Front 87

Active Site

Back 87

Site on the enzyme's surface where the substrates bind and are acted upon

Front 88

Factors affecting enzyme function

Back 88

• pH
• Temp.
• inhibitors
• activators

Front 89

Enzyme Inhibition:

Back 89

1. Competitive- substances competes with the substrate for the active site, makes active site unavailable
2. Noncompetitive- substance binds to a second binding site (the allosteric site), changing the shape of the enzyme & locking it into and active shape. (allosteric inhibitor)

Front 90

Allosteric Activator

Back 90

Binds to the allosteric site, locking the enzyme into an active form (so allosteric enzymes have 2 binding sites - the active and the allosteric site)

Front 91

ATP

Back 91

Immediate source of energy for all the cell's work. releases energy when phosphate groups are chopped off. (But it takes energy to put a phosphate back onto ADP to regenerate ATP - energy comes from the breakdown of food molecules)

Front 92

Metabolic Pathways

Back 92

1. Degradative
2. Biosynthetic

Front 93

Degradative

Back 93

• Exergonic
• - NET G
• Release energy by breaking down complex molecules to simpler ones

Front 94

Biosynthetic

Back 94

• Endergonic
• + NET G
• Require energy, assemble complex molecules from simpler ones

Front 95

Feedback Inhibition

Back 95

Type of enzyme inhibition where the final product of a metabolic pathway is the allosteric inhibitor of the first enzyme n the pathway - shuts off the entire pathway

Front 96

Multicellular organisms use a variety of chemical signals

Back 96

Which ones a specific cell responds to depends on the protein receptors on or in the cell

Front 97

Types of cell signaling:

Back 97

1. Direct contact
2. Paracrine Signaling
3. Endocrine Signaling
4. Synaptic Signaling

Front 98

Direct Contact

Back 98

Molecules of adjacent cells bind & interact

Front 99

Paracrine Signaling

Back 99

Signal molecules diffuse through extracellular fluid to neighboring cells. The signals are short lived & local

Front 100

Endocrine Signaling

Back 100

Signal molecules (hormones) are released into the blood stream. The target cells may be very distant, and the effects are long-lasting.

Front 101

Synaptic Signaling

Back 101

Nerve cells send very long extensions to the target cells & release neurotransmitters very close to the target cell. The neurotransmitters cross the synapse & act on the target cell - effects are very brief

Front 102

Cell Receptors

Back 102

1. Intracellular
2. Cell Surface Receptors

Front 103

Intracellular

Back 103

Within cell. Signal molecule must cross the cell membrane & bind to the receptor

Front 104

Cell Surface Receptors

Back 104

Receptor is on the plasma membrane - initiates some sequence of events within the cell

Front 105

Cell Surface Markers

Back 105

Identify the cell

Front 106

Intercellular Adhesion Proteins

Back 106

1. Tight junctions - leakproof barrier
2. Anchoring junctions - "button" cells together
3. Communicating junctions -

-gap junctions - (animal cells) - protein-lined channels between neighboring cells

-plasmodesmata (plant cells) - more complex, go through openings in cell walls, lined with plasma membrane & contain tubules of ER - connecting the ERs of the two cells