Chapter 3

Question 1

What is matter?

Answer 1

Anything that takes up space
The smallest unit of matter is the atom

Question 2

What are molecules?

Answer 2

Two or more atoms of the same or different elements joined by chemical bonds

Question 3

What are compounds?

Answer 3

A substance composed of two or more different atoms

All compounds are molecules but not all molecules are compounds

Question 4

What is the atomic nucleus?

Answer 4

The center of an atom and made up of protons and neutrons

Question 5

What is the Valence Shell

Answer 5

The outmost shell of an atom

Question 6

What are Valence Electrons?

Answer 6

They are located on the atom’s outermost shell (the valence shell)

Question 7

What is the #1 Golden Rule regarding atoms?

An atom’s quest

Answer 7

An atom’s quest is to have fully occupied valence shells

Question 8

What are covalent bonds?

Answer 8

Strongest of all bonds formed between atoms by sharing electrons

Question 9

What are ionic bonds?

Answer 9

Ionic bonds form when one atom gives up one or more electrons to another atom

Question 10

What is a solution?

Answer 10

A homogeneous mixture of two or more compounds. Involves a solvent (major component), and a solute (minor component)

If water is the solvent, then it is an aqueous solution

Question 11

Explain the role of blood capillaries

Answer 11

Blood flows through it, forcing plasma out of tiny openings and pools around the body’s cells. Cells bathe in this solution of water and nutrients. The cells take up these nutrients to meet their cellular need.

Question 12

What is electronegativity?

What is it considered?

Answer 12

The ability of an atom to attract the electrons in a bond

Golden Rule #2

Question 13

What are polar molecules?

Answer 13

Have a partial positive charge on one part of the molecule and a partial negative charge in another part

Question 14

What are hydrogen bonds?

Answer 14

Bond between an electronegative atom and a hydrogen atom bonded to another electronegative atom

Can occur between molecules or within parts of a single molecule

Question 15

How does starch behave in water?

Answer 15

It does not dissolve in cold water because plants pack starch into tight, dense granules.
If water is heated, hydrogen bonds between starch threads and water will be made, creating a sort of starch gel

Question 16

What are enzymes?

Answer 16

Proteins that facilitate chemical reactions without being changed in the process. They easily dissolve in solution. In the absence of enzymes, absorption of nutrients would be impossible. Specific 3D structure via hydrogen bonds

Enzymes that work to digest food in your mouth will not work in your stomach due to changes in pH causing enzymes to change shape.

Question 17

What is pH?

How is it meaured?

Answer 17

The unit of measure expressing a substance’s acidity or alkalinity. pH is crucial to activating enzymes to facilitate digestion. pH is a measure of the concentration of hydrogen ions (H+).

Higher concentration = lower pH. The scale ranges from 0 to 14. Each whole number increase, concentration of hydrogen ions decreases 10x. Hydrogen ions interfere with hydrogen bonds.

Question 18

What is the Digestive system?

Answer 18

Set of organs that work cooperatively to digest food and deliver nutrients

Question 19

How are cells, tissues and organs related? What do they form?

Answer 19

Cell → Tissue (Collection of similar cells) → Organ (Collection of various types of tissues with related functions) → System (Collection of organs with related functions)

Question 20

What are the types of tissues?

Answer 20

(1) Epithelial
(2) Connective
(3) Muscle
(4) Neural

Question 21

What is Epithelial tissue?

Answer 21

Epithelial cells line the lining of the entire alimentary canal and allow smooth passage of food. They also synthesize and excrete enzymes for digestion and absorb nutrients

Question 22

What is the digestive organ system?

What is its transit time?

Answer 22

A hollow tube from mouth to anus. The inside of this tube is called lumen.

The transit time of food is 24 to 72 hours.

Question 23

What are the functions of the digestive system?

Answer 23

(1) Digestion
(2) Absorption
(3) Elimination

Functions aided by epithelial cells make up innermost lining of digestive tract.

Question 24

What are the substances released in the digestive organ system? What are their purposes?

Answer 24

(1) Enzymes for digestion
(2) Hormones for communication with other members of system
(3) Mucus to facilitate and protect from the passage of irritating substances

Question 25

When eating, what happens in the mouth and stomch?

Answer 25

Performance of both chemical and mechanical breakdown of food. Muscular contractions churn the food. When mixed with stomach secretions, food becomes chyme → goes to small intestine.

Question 26

When eating, what happens in the small intestine?

Answer 26

Folds along the lumen have these tiny finger-like projections called villi. They are lined with epithelial cells help nutrients absorb quickly. Small intestine has a high turnover rate for its cells. | Villi (with both blood and lymphatic vessels)

Question 27

Can you explain the process of absorption?

Answer 27

Absorption is the transfer of nutrients from the gastrointestinal tract into the blood or lymph vessels

Question 28

What are the accessory organs?

Answer 28

Substances produced in the pancreas, gallbladder, and liver travel through tiny ducts and are released into the duodenum

Question 29

Explain the process of nutrient delivery

Answer 29

Nutrients from the intestines are delivered to the liver via the “Hepatic portal vein.” Blood vessels in the liver split into thousands of tiny “capillaries,” giving the liver cells the first dibs on nutrients. Then, the nutrient-rich blood leaves the liver to deliver to the rest of the body’s cells.

Question 30

What does the process of "elimination" refer to? | What are its ties with gut flora?

Answer 30

Elimination: process of removing solid waste from the body (eliminated through the large intestine). The large intestine absorbs water and some minerals. ## Footnote Microbe diversity in the large intestine. They feast on fiber.

Question 31

What is included in the network of blood vessels?

Answer 31

Includes: Arteries, Arterioles, Capillaries, Venules, Veins

Question 32

What is the octet rule?

Answer 32

Atoms form covalent bonds to achieve stable outer shells (8 electrons, or 2 for hydrogen)

Question 33

What are free radicals?

Answer 33

Molecules missing electrons; highly reactive and damaging