basic chemistry

Essentials of Human Anatomy & Physiology

Basic ChemistryBasic Chemistry

Biochemistry: Essentials for LifeBiochemistry: Essentials for Life

Slide 2.21Slide 2.21Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

• Organic compounds

• Contain carbon

• Most are covalently bonded

• Example: C6H12O6 (glucose)

• Inorganic compounds

• Lack carbon

• Tend to be simpler compounds

• Example: H2O (water)

Important Inorganic CompoundsImportant Inorganic Compounds


• Water

• Most abundant inorganic compounds

• Vital properties

• High heat capacity

• Polarity/solvent properties

• Chemical reactivity

• Cushioning



• Salts

• Easily dissociate into ions in the presence of water

• Vital to many body functions

• Include electrolytes which conduct electrical currents



• Acids

• Can release detectable hydrogen ions

• Bases

• Proton acceptors

• Neutralization reaction

• Acids and bases react to form water and a salt

pHpH


• Measures relative concentration of hydrogen ions

• pH 7 = neutral

• pH below 7 = acidic

• pH above 7 = basic

• Buffers

• Chemicals that can regulate pH change

Figure 2.11

Important Organic CompoundsImportant Organic Compounds


• Carbohydrates

• Contain carbon, hydrogen, and oxygen

• Include sugars and starches

• Classified according to size

• Monosaccharides – simple sugars

• Disaccharides – two simple sugars joined by dehydration synthesis

• Polysaccharides – long branching chains of linked simple sugars

CarbohydratesCarbohydrates


Figure 2.12a, b

CarbohydratesCarbohydrates


Figure 2.12c



• Lipids

• Contain carbon, hydrogen, and oxygen

• Carbon and hydrogen outnumber oxygen

• Insoluble in water


Slide Slide 2.30a2.30a

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

• Common lipids in the human body

• Neutral fats (triglycerides)

• Found in fat deposits

• Composed of fatty acids and glycerol

• Source of stored energy


Slide Slide 2.30b2.30b


• Common lipids in the human body (continued)

• Phospholipids

• Form cell membranes

• Steroids

• Include cholesterol, bile salts, vitamin D, and some hormones


Figure 2.14a, b

LipidsLipids


Figure 2.14c

CholesterolCholesterol




• Proteins

• Made of amino acids

• Contain carbon, oxygen, hydrogen, nitrogen, and sometimes sulfur




• Account for over half of the body’s organic matter

• Provides for construction materials for body tissues

• Plays a vital role in cell function

• Act as enzymes, hormones, and antibodies

EnzymesEnzymes


• Act as biological catalysts

• Increase the rate of chemical reactions

Figure 2.16



• Nucleic Acids

• Provide blueprint of life

• Nucleotide bases

• A = Adenine

• G = Guanine

• C = Cytosine

• T = Thymine

• U = Uracil

• Make DNA and RNA



• Deoxyribonucleic acid (DNA)

• Organized by complimentary bases to form double helix

• Replicates before cell division

• Provides instruction for every protein in the body Figure 2.17c



• Adenosine triphosphate (ATP)

• Chemical energy used by all cells

• Energy is released by breaking high energy phosphate bond

• ATP is replenished by oxidation of food fuels

Adenosine Triphosphate (ATP)Adenosine Triphosphate (ATP)


Figure 2.18a

Essentials of Human Anatomy & Physiology

Cells and TissuesCells and Tissues

Cells and TissuesCells and Tissues


Carry out all chemical activities needed to sustain life

Cells are the building blocks of all living things

Tissues are groups of cells that are similar in structure and function

Anatomy of the CellAnatomy of the Cell


Cells are not all the same

All cells share general structures

Cells are organized into three main regions Nucleus

Cytoplasm

Plasma membrane

Figure 3.1a

The NucleusThe Nucleus


Control center of the cell

Contains genetic material (DNA)

Three regions

Nuclear membrane

Nucleolus

Chromatin Figure 3.1b

Cytoplasmic OrganellesCytoplasmic Organelles


Figure 3.4

Cellular Physiology:Cellular Physiology:Membrane TransportMembrane Transport


Membrane Transport – movement of substance into and out of the cell

Transport is by two basic methods Passive transport

No energy is required

Active transport

The cell must provide metabolic energy

Solutions and TransportSolutions and Transport


Solution – homogeneous mixture of two or more components Solvent – dissolving medium

Solutes – components in smaller quantities within a solution

Intracellular fluid – nucleoplasm and cytosol

Interstitial fluid – fluid on the exterior of the cell

Selective PermeabilitySelective Permeability


The plasma membrane allows some materials to pass while excluding others

This permeability includes movement into and out of the cell

Passive Transport ProcessesPassive Transport Processes


Diffusion Particles tend to distribute themselves

evenly within a solution

Movement is from high concentration to low concentration, or down a concentration gradient

Figure 3.8




Types of diffusion

Simple diffusion

Unassisted process

Solutes are lipid-soluble materials or small enough to pass through membrane pores




Types of diffusion

Osmosis – simple diffusion of water

Highly polar water easily crosses the plasma membrane

Facilitated diffusion

Substances require a protein carrier for passive transport

Diffusion through the Plasma Diffusion through the Plasma MembraneMembrane


Figure 3.9



Filtration

Water and solutes are forced through a membrane by fluid, or hydrostatic pressure

A pressure gradient must exist

Solute-containing fluid is pushed from a high pressure area to a lower pressure area

Active Transport ProcessesActive Transport Processes


Transport substances that are unable to pass by diffusion They may be too large

They may not be able to dissolve in the fat core of the membrane

They may have to move against a concentration gradient

Two common forms of active transport Solute pumping

Bulk transport




Solute pumping

Amino acids, some sugars and ions are transported by solute pumps

ATP energizes protein carriers, and in most cases, moves substances against concentration gradients




Bulk transport Exocytosis

Moves materials out of the cell

Material is carried in a membranous vesicle

Vesicle migrates to plasma membrane

Vesicle combines with plasma membrane

Material is emptied to the outside




Bulk transport

Endocytosis

Extracellular substances are engulfed by being enclosed in a membranous vescicle

Types of endocytosis

Phagocytosis – cell eating

Pinocytosis – cell drinking

Cell Life CycleCell Life Cycle


Cells have two major periods

Interphase

Cell grows

Cell carries on metabolic processes

Cell division

Cell replicates itself

Function is to produce more cells for growth and repair processes

DNA ReplicationDNA Replication


Genetic material duplicated and readies a cell for division into two cells

Occurs toward the end of interphase

DNA uncoils and each side serves as a template

Figure 3.13

Events of Cell DivisionEvents of Cell Division


Mitosis Division of the nucleus

Results in the formation of two daughter nuclei

Cytokinesis Division of the cytoplasm

Begins when mitosis is near completion

Results in the formation of two daughter cells

Stages of MitosisStages of Mitosis



Interphase

No cell division occurs

The cell carries out normal metabolic activity and growth

Prophase

First part of cell division

Centromeres migrate to the poles




Metaphase

Spindle from centromeres are attached to chromosomes that are aligned in the center of the cell



Anaphase

Daughter chromosomes are pulled toward the poles

The cell begins to elongate

Telophase

Daughter nuclei begin forming

A cleavage furrow (for cell division) begins to form




Figure 3.14; 1




Figure 3.14; 2

Protein SynthesisProtein Synthesis


Gene – DNA segment that carries a blueprint for building one protein

Proteins have many functions

Building materials for cells

Act as enzymes (biological catalysts)

RNA is essential for protein synthesis

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