Chapter 2: Levels of Organization of the Human Body

Chemical Level

It is the simplest level—deals with the body’s chemistry and involves individual atoms and molecules.

Organelle Level

In this level, the molecules work together as organelles to perform specific functions.

Cellular Level

In this level, the organelles work together to perform specific functions for a cell.

Cell

It is the basic unit of life.

Tissue Level

In this level, the body is composed of trillions of cells that work together to complete specific functions.

Organ Level

In this level, the different tissues work together to complete specific functions.

System Level

The organs work together in this level to perform functions such as digestion and respiration.

Human

All the body systems must work together to accomplish the entire organism’s functions. In this case, the organism is a _____.

Organism Level

This level is the most complex level.

Matter

All solids, liquids, and gases are composed of?

Matter

It is defined as anything that takes up space and has mass.

Element

What is the simplest chemical component of matter?

Element

This has a unique set of chemical properties and cannot be separated by chemical methods.

Atom

It is the smallest piece of an element still exhibiting the element’s unique set of chemical properties is an ____?

Protons, Electrons, and Neutron

Atoms are composed of these three.

Atomic number

The number of protons for each element is fixed and is indicated by the?

Atomic mass

This is the combined number protons and neutrons.

Isotopes

These type of atoms have the same number of protons as every other atom of that element but have different number of neutrons.

Radioisotopes

Some isotopes are unstable and freely emit particles to get to a more stable form, if they do, they are called ______.

Radioactivity

The decay of radioisotopes is called?

Radioactivity

This can be very useful in medicine for diagnosis and treatment.

Molecules

Atoms will bind with other atoms to form these in order to fill their outer shells with electrons. This makes them more stable.

Moleculess

It is a two or more atoms bonded together.

Covalent bond

This very stable bond is often formed by carbon atoms, occurs when two or mor atoms share electrons to fill their outer shells.

Ionic bond

This type of bond have two or more atoms bind to form a molecule by giving up or receiving electrons from each other to fill their outer shells.

Ions

Atoms with a charged are called?

Electrolytes

These ions are capable of conducting electricity.

Hydrogen bond

This bond is a weak bond that occurs between a positively charged hydrogen atom and a negatively charged oxygen or nitrogen atom.

Hydrogen bond

These type of bonds are responsible for holding water molecules together.

Deoxyribonucleic acid (DNA)

Hydrogen bonds are also found in protein and in?

Water

This serves as a key functions in the body.

Electrolytes

Water chemically separates ionically bonded molecules into individual ions called?

Water

This is used for temperature regulation.

It is a high heat capacity to maintain body temperature and can also be used to cool the body when it evaporates from the surface as sweat.

Solution

This is composed of two basic parts: one or more solutes and a solvent.

Concentration

This refers to the amount of solute present in a solution relative to the amount of solvent.

Tonicity

This is used to when comparing solutions.

Hypertonic, Isotonic, and Hypotonic

When compared to another solution, a solution may be?

Hypertonic

If it is more concentrated with solutes than the other solution, this solution is?

Isotonic

If it has the concentration with solutes than the other solution, this solution is?

Hypotonic

If it is less concentrated with solutes than the other solution, this solution is?

Acid

This is a molecule that releases a hydrogen ion (H⁺) when added to water.

Base

This is a molecule that will accept the hydrogen ion, often by releasing a hydroxide ion (OH^-) when added to water.

pH (potential of hydrogen)

You can measure the strength of acids and bases by using this scale.

Acidic

The lower than 7 the pH is, the more hydrogen ions the substance has to release; this makes is more?

Basic

The higher than 7 the pH is, the more hydroxide ions the substance has to release; this makes is more?

Acidosis

A blood pH lower than 7.35 is considered as?

Alkalosis

A blood pH higher than 7.45 is considered as?

Organic

In common usage, this term refers to something that is healthy, free of pesticides, and naturally grown.

Organic molecules

These molecules come from life and must contain atoms of the elements carbon and hydrogen.

Carbohydrates, lipids, proteins, and nucleic acids

What are the four major types of organic molecules?M

Monossacharides

What are the building blocks of carbohydrates?

Glucose

Examples of Carbohydrate:

It is a sugar found in blood and is the main energy source for cells.

Glycogen

Examples of Carbohydrate:

It is a starch found in muscles and the liver.

• It is a stored energy source (glucose is converted to glycogen for storage).

Fatty acids and glycerol

What are the building blocks of lipids?

Fats

Examples of Lipid:

Adipose tissue and is a stored energy.

Steroids

Examples of Lipid:

Hormones found in blood and regulate the body.

Phospholipids

Examples of Lipid:

These are cell membranes that gives structure to cell and regulate what goes in and out of the cell.

Amino acids

What are the building blocks of protein?

Keratin and collagen

Examples of Protein:

These can be found in in the skin and they give strength to the skin.

Hormones

Examples of Protein:

These can be found in the blood and regulate the body.

Transport proteins

Examples of Protein:

These proteins can also be found in the blood. They transport other molecules.

Enzymes

Examples of Protein:

These protein are everywhere in the body that aids in chemical reaction.

Antibodies

Examples of Protein:

These are found in the blood and fight foreign invaders.

Muscle proteins

Examples of Protein:

Found in the muscles and allow for contraction of muscles.

Binding and receptor proteins

Examples of Protein:

These are found in cell membranes and hold cells together.

Nucelotides

What are the building blocks of Nucleic acid?

Deoxyribonucleic acid (DNA)

Examples of Nucleic acid:

The nucleus of a cell and it is the genetic information.

Ribonucleic acid (RNA)

Examples of Nucleic acid:

Can be found in many places in a cell. It processes the genetic information.

Disaccharide

This is the result when you combine two monosaccharides to form a single molecule.

Polysaccharide

If you string many monosaccharides together like beads in a necklace to form a single molecule, this is called a?

Polysaccharide

Glycogen (a starch) is an example of a?

Carbohydrates

These are an energy source for the cell.

Proteins

These organic molecules contain nitrogen in addition to carbon, hydrogen, and oxygen.

First level

Chemical level:

Amino acids are bonded together to form a chain.

Second level

Chemical level:

Attraction of some amino acids in the chain to other amino acids causes parts of the chain to pleat as a ribbon or coil as a rod.

Third level

Chemical level:

The pleated ribbons and coiled rods fold into a three-dimensional structure defining the protein’s unique shape.

Fourth level

Chemical level:

Two or more uniquely shaped proteins may be connected to form a single protein molecule.

Nucleic acids

These organic molecules are composed of carbon, hydrogen, oxygen, nitrogen, and phosphorus.

Nucleotides

These are composed of a sugar, a phosphate double strand (double helix), as in deoxyribonucleic acid (DNA), or in a single strand, as in ribonucleic acid (RNA).

• Guanine (G)

• Cytosine (C)

• Adenine (A)

• Thymine (T)

What are the nitrogenous bases in DNA?

Uracil (U)

In RNA, this nitrogenous base is substituted for thymine.

Cytosine

Guanine always pairs with?

Thymine

Adenine always pair with?

Genetic code

Your DNA contains all of the genetic information that is you. It is written in DNA language called the?

Codon

This a sequence of three nucleotides which together form a unit of genetic code in a DNA or RNA molecule.

Gene

It is the sequence of DNA that must be read to give you the directions to make one specific protein.

Cystic fibrosis

It is a genetic disorder that reduces life expectancy to approximately 35 years, results when just 3 of the 250,000 base pairs of nucleotides are missing.

Metabolism

This is the sum total of all the chemical reactions that take place in the human body.

Cellular Respiration

This is one of the most important chemical reactions in the body. It is a metabolic pathway that breaks down glucose and produces ATP.

Adenosibe triphosphate (ATP)

The energy released from a glucose molecule in cellular respiration must be converted to a usable form.

Adenosibe triphosphate (ATP)

This contains the usable form of energy for the cell. This energy is released from a glucose molecule’s chemical bonds via cellular respiration, and then it helps form a chemical bond between adenosine diphosphate and a third phosphate.

Organelle

Molecules of different types come together to form an?

Organelles

These are specialized, membrane-bound structures of cells.

Cytoplasm

The organelles are suspended within the cell in a fluid called _____, which is a solution.

• This contains electrolytes, nutrients, wastes, and gases (such as oxygen and carbon dioxide) and the solutes and water as the solvent.

Cytoskeleton

A ______ of protein fibers organizes the organelles within the cytoplasm.

Cell membrane (plasma membrane)

Cell Structures and Organelles:

• Phospholipid bilayer

• Found in all cells

• Gives structure to cell, defining what is intracellular (inside the cell) and what is extracellular (outside the cell); regulates what may enter or leave the cell.

Cilla

Cell Structures and Organelles:

• Hairlike extensions of cell membrane

• Found in cells needing to move materials outside themselves

• Move in wavelike motion to move materials past the cell

Microvilli

Cell Structures and Organelles:

• Hairlike extensions of cell membrane

• Found in cells requiring extra surface area

• Provide extra surface area for the cell

Nucleus

Cell Structures and Organelles:

• Enclosed by a membrane

• Found in all cells except red blood cells

• Houses DNA

Mitochondria

Cell Structures and Organelles:

• Rod-shaped; enclosed by a membrane

• Found in large numbers in cells with high energy demands

• Carry out cellular respiration and processes the energy released to form ATP