human anatomy & physiology chapter 2: chemistry comes...

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Human Anatomy & Physiology

Chapter 2: Chemistry Comes

Alive


MATTER VS. ENERGY


Which of the following is not an

example of matter?

1) Blood plasma

2) The air we breathe

3) An arm bone

4) Electricity


Which of the following is an example of

conversion of potential energy to kinetic

energy?

1) Synthesis of ATP from glucose

2) ATP hydrolysis to drive muscle

contraction

3) Digesting a protein in the stomach


COMPOSITION OF MATTER


Figure 2.1 Two models of the structure of an atom.

(a) Planetary model (b) Orbital model

Helium atom

2 protons (p+)

2 neutrons (n0)

2 electrons (e–)

Helium atom

2 protons (p+)

2 neutrons (n0)

2 electrons (e–)

Nucleus Nucleus

Proton Neutron Electron

cloud

Electron


Figure 2.2 Atomic structure of the three smallest atoms.

Proton

Neutron

Electron

Helium (He)

(2p+; 2n0; 2e–)

Lithium (Li)

(3p+; 4n0; 3e–)

Hydrogen (H)

(1p+; 0n0; 1e–)


Figure 2.3 Isotopes of hydrogen.

Proton

Neutron

Electron

Deuterium (2H)

(1p+; 1n0; 1e–)

Tritium (3H)

(1p+; 2n0; 1e–)

Hydrogen (1H)

(1p+; 0n0; 1e–)


The subatomic particle which

determines an atom’s identity is the…

1) Electron

2) Neutron

3) Proton

4) Quark


The element lithium has 3 protons and 4

neutrons in its nucleus. Its mass

number is …

1) 7

2) 3

3) 4

4) 1


The element lithium has 3 protons and 4

neutrons in its nucleus. Its atomic

number is …

1) 7

2) 3

3) 4

4) 1


MOLECULES AND MIXTURES


Figure 2.4 The three basic types of mixtures.

Solution

Solute

particles

Solute

particles Solute

particles

Solute particles are very

tiny, do not settle out or

scatter light.

Colloid

Solute particles are larger

than in a solution and scatter

light; do not settle out.

Suspension

Solute particles are very

large, settle out, and may

scatter light.

Example

Mineral water

Example

Gelatin

Example

Blood

Water with particles dissolved into it

such that the particles do not settle out,

and are invisible is a…

1) suspension

2) colloid

3) solution

4) all of the above


CHEMICAL BONDS


Figure 2.5a Chemically inert and reactive elements.

Helium (He)

(2p+; 2n0; 2e–)

Neon (Ne)

(10p+; 10n0; 10e–)

2e 2e 8e

(a) Chemically inert elements

Outermost energy level (valence shell) complete


Figure 2.5b Chemically inert and reactive elements.

2e 4e

2e 8e

1e

(b) Chemically reactive elements

Outermost energy level (valence shell) incomplete

Hydrogen (H)

(1p+; 0n0; 1e–)

Carbon (C)

(6p+; 6n0; 6e–)

1e

Oxygen (O)

(8p+; 8n0; 8e–) Sodium (Na)

(11p+; 12n0; 11e–)

2e 6e


Figure 2.6a Formation of an ionic bond.

Sodium atom (Na)

(11p+; 12n0; 11e–)

Chlorine atom (Cl)

(17p+; 18n0; 17e–)

(a) Sodium gains stability by losing one electron, and

chlorine becomes stable by gaining one electron.


Figure 2.6b Formation of an ionic bond.

Sodium ion (Na+) Chloride ion (Cl–)

Sodium chloride (NaCl)

+ –

(b) After electron transfer, the oppositely

charged ions formed attract each other.


Figure 2.6c Formation of an ionic bond.

CI–

Na+

(c) Large numbers of Na+ and Cl

– ions

associate to form salt (NaCl) crystals.


Figure 2.7a Formation of covalent bonds.

+

Hydrogen

atoms

Carbon

atom

Molecule of

methane gas (CH4)

Structural

formula

shows

single

bonds.

(a) Formation of four single covalent bonds:

carbon shares four electron pairs with four

hydrogen atoms.

or

Resulting molecules Reacting atoms


Figure 2.7b Formation of covalent bonds.

or

Oxygen

atom

Oxygen

atom

Molecule of

oxygen gas (O2)

Structural

formula

shows

double

bond. (b) Formation of a double covalent bond: Two

oxygen atoms share two electron pairs.


+


Figure 2.7c Formation of covalent bonds.

+ or

Nitrogen

atom

Nitrogen

atom

Molecule of

nitrogen gas (N2)

Structural

formula

shows

triple

bond. (c) Formation of a triple covalent bond: Two

nitrogen atoms share three electron pairs.



Figure 2.8 Carbon dioxide and water molecules have different shapes, as illustrated by molecular models.


Figure 2.10a Hydrogen bonding between polar water molecules.

(a) The slightly positive ends (+) of the water

molecules become aligned with the slightly

negative ends (–) of other water molecules.

+

–

–

– –

–

+

+

+

+

+

Hydrogen bond

(indicated by

dotted line)


A bond resulting from two atoms

sharing a pair of electrons is a(n)…

1) ionic bond

2) covalent bond

3) hydrogen bond

4) double bond


A bond resulting from one atom

donating an electron to another is a(n)…

1) ionic bond

2) covalent bond

3) hydrogen bond

4) double bond


Hydrogen bonds are like ionic bonds

because…

1) both form molecules

2) both are very strong bonds

3) both occur between like-charged

atoms

4) both are due to opposite charge

attractions


CHEMICAL REACTIONS


Figure 2.11a Patterns of chemical reactions.

Example

Amino acids are joined together to

form a protein molecule.

(a) Synthesis reactions

Smaller particles are bonded

together to form larger,

more complex molecules.

Amino acid

molecules

Protein

molecule


Figure 2.11b Patterns of chemical reactions.

Example

Glycogen is broken down to release

glucose units.

Bonds are broken in larger

molecules, resulting in smaller,

less complex molecules.

(b) Decomposition reactions

Glucose

molecules

Glycogen


Figure 2.11c Patterns of chemical reactions.

Example

ATP transfers its terminal phosphate

group to glucose to form glucose-phosphate.

Bonds are both made and broken

(also called displacement reactions).

(c) Exchange reactions

Glucose Adenosine triphosphate (ATP)

Adenosine diphosphate (ADP) Glucose

phosphate

+

+


BIOCHEMISTRY

INORGANIC COMPOUNDS


Figure 2.12 Dissociation of salt in water.

Water molecule

Ions in solution Salt crystal

–

+

+


ACIDS AND BASES


Figure 2.13 The pH scale and pH values of representative substances.

Concentration (moles/liter)

[OH–]

100 10–14

10–1 10–13

10–2 10–12

10–3 10–11

10–4 10–10

10–5 10–9

10–6 10–8

10–7 10–7

10–8 10–6

10–9 10–5

10–10 10–4

10–11 10–3

10–12 10–2

10–13 10–1

[H+] pH

Examples

1M Sodium

hydroxide (pH=14)

Oven cleaner, lye

(pH=13.5)

Household ammonia

(pH=10.5–11.5)

Neutral

Household bleach

(pH=9.5)

Egg white (pH=8)

Blood (pH=7.4)

Milk (pH=6.3–6.6)

Black coffee (pH=5)

Wine (pH=2.5–3.5)

Lemon juice; gastric

juice (pH=2)

1M Hydrochloric

acid (pH=0) 10–14 100

14

13

12

11

10

9

8

7

6

5

4

3

2

1

0


A substance that is very acidic may

have a pH of 1-2; this means that it…

1) has a high concentration of OH- ions

2) has an equal concentration of H+

and OH- ions

3) has a low concentration of H+ ions

4) has a high concentration of H+ ions


ORGANIC COMPOUNDS


An organic compound is one that…

1) is natural

2) is in the human body

3) contains carbon

4) is polar


Figure 2.14a Biological molecules are formed from their monomers or units by dehydration synthesis and broken

down to the monomers by hydrolysis reactions.

+

Monomers linked by covalent

bond

(a) Dehydration synthesis

Monomers are joined by removal of OH from one monomer

and removal of H from the other at the site of bond formation.

Monomer 1 Monomer 2


Figure 2.14b Biological molecules are formed from their monomers or units by dehydration synthesis and broken


Monomers linked by covalent bond

+

(b) Hydrolysis

Monomers are released by the addition of a water molecule,

adding OH to one monomer and H to the other.

Monomer 1 Monomer 2


Figure 2.14c Biological molecules are formed from their monomers or units by dehydration synthesis and broken


Glucose Fructose

Water is released

Water is

Consumed Sucrose

(c) Example reactions

Dehydration synthesis of sucrose and its

breakdown by hydrolysis

+


Figure 2.15a Carbohydrate molecules important to the body.

Example

Hexose sugars (the hexoses shown

here are isomers)

Example

Pentose sugars

Glucose Fructose Galactose Deoxyribose Ribose

(a) Monosaccharides

Monomers of carbohydrates


Figure 2.15b Carbohydrate molecules important to the body.

Example

Sucrose, maltose, and lactose

(these disaccharides are isomers)

Glucose Fructose Glucose Glucose Glucose

Sucrose Maltose Lactose

Galactose

(b) Disaccharides

Consist of two linked monosaccharides


Figure 2.15c Carbohydrate molecules important to the body.

Example

This polysaccharide is a simplified representation of

glycogen, a polysaccharide formed from glucose units.

(c) Polysaccharides

Long branching chains (polymers) of linked monosaccharides

Glycogen


The major function of carbohydrates in

the body is…

1) protein synthesis

2) as cellular fuel

3) being a genetic blueprint

4) forming the cell membrane bilayer


Figure 2.16a Lipids.

Glycerol

+

3 fatty acid chains Triglyceride,

or neutral fat

3 water

molecules

(a) Triglyceride formation

Three fatty acid chains are bound to glycerol by

dehydration synthesis


Figure 2.16b Lipids.

Phosphorus-

containing

group (polar

“head”)

Example

Phosphatidylcholine

Glycerol

backbone

2 fatty acid chains

(nonpolar “tail”)

Polar

“head”

Nonpolar “tail”

(schematic phospholipid)

(b) “Typical” structure of a phospholipid molecule

Two fatty acid chains and a phosphorus-containing group are

attached to the glycerol backbone.


Figure 2.16c Lipids.

Example

Cholesterol (cholesterol is the basis for all steroids formed in the body)

(c) Simplified structure of a steroid

Four interlocking hydrocarbon rings form a steroid.


Which of the following is NOT a type of

lipid?

1) steroid

2) triglyceride

3) disaccharide

4) fatty acid


Figure 2.17a Amino acid structures.

(a) Generalized

structure of all amino acids.

Amine group

Acid group


Figure 2.17b Amino acid structures.

(b) Glycine

is the simplest amino acid.


Figure 2.17c Amino acid structures.

(c) Aspartic acid

(an acidic amino acid) has an acid group (—COOH) in the R group.


Figure 2.17d Amino acid structures.

(d) Lysine

(a basic amino acid) has an amine group (—NH2) in the R group.


Figure 2.17e Amino acid structures.

(e) Cysteine

(a basic amino acid) has a sulfhydryl (—SH) group in the R group, which suggests that this amino acid is likely to participate in intramolecular bonding.


Figure 2.18 Amino acids are linked together by peptide bonds.

Amino acid Amino acid Dipeptide

Dehydration synthesis:

The acid group of one amino acid is bonded to the amine group of the next, with loss of a water molecule.

Hydrolysis: Peptide bonds linking amino acids together are broken when water is added to the bond.

+

Peptide bond


Figure 2.19 Levels of protein structure.

Secondary structure:

The primary chain forms

spirals (-helices) and

sheets (-sheets).

Tertiary structure:

Superimposed on secondary structure.

-Helices and/or -sheets are folded up

to form a compact globular molecule

held together by intramolecular bonds.

Quaternary structure:

Two or more polypeptide chains, each

with its own tertiary structure, combine

to form a functional protein.

Tertiary structure of prealbumin

(transthyretin), a protein that

transports the thyroid hormone

thyroxine in serum and cerebro-

spinal fluid.

Quaternary structure of a

functional prealbumin molecule.

Two identical prealbumin subunits

join head to tail to form the dimer.

Amino acid Amino acid Amino acid Amino acid Amino acid

� -Helix: The primary chain is coiled

to form a spiral structure, which is

stabilized by hydrogen bonds. � -Sheet: The primary chain “zig-zags” back

and forth forming a “pleated” sheet. Adjacent

strands are held together by hydrogen bonds.

(a) Primary structure:

The sequence of

amino acids forms the

polypeptide chain.

(b)

(c)

(d)


Figure 2.19a Levels of protein structure.

(a) Primary structure:

The sequence of amino acids forms the polypeptide chain.

Amino acid Amino acid Amino acid Amino acid Amino acid


Figure 2.19b Levels of protein structure.

-Helix: The primary chain is coiled

to form a spiral structure, which is stabilized by hydrogen bonds.

-Sheet: The primary chain “zig-zags” back

and forth forming a “pleated” sheet. Adjacent

strands are held together by hydrogen bonds.

(b) Secondary structure:

The primary chain forms spirals (-helices) and sheets (-sheets).


Figure 2.19c Levels of protein structure.

Tertiary structure of prealbumin

(transthyretin), a protein that

transports the thyroid hormone

thyroxine in serum and cerebro-

spinal fluid.

(c) Tertiary structure:

Superimposed on secondary structure. -Helices and/or -sheets are

folded up to form a compact globular molecule held together by

intramolecular bonds.


Figure 2.19d Levels of protein structure.

Quaternary structure of

a functional prealbumin

molecule. Two identical

prealbumin subunits

join head to tail to form

the dimer.

(d) Quaternary structure:

Two or more polypeptide chains, each with its own tertiary structure,

combine to form a functional protein.


Which of the following is the building

block for proteins?

1) monosaccharides

2) fatty acids

3) nucleotides

4) amino acids


“Tertiary structure” of a protein refers

to…

1) its amino acid sequence

2) its 3-dimensional structure

3) how it interacts with other amino

acid sequences

4) the alpha helices and beta sheets


Figure 2.20 Enzymes lower the activation energy required for a reaction to proceed rapidly.

Activation

energy

required

Less activation

energy required

WITHOUT ENZYME WITH ENZYME

Reactants

Product Product

Reactants


Figure 2.21 Mechanism of enzyme action.

Substrates (S)

e.g., amino acids

Enzyme (E)

Enzyme-substrate

complex (E-S) Enzyme (E)

Product (P)

e.g., dipeptide

Energy is absorbed; bond is formed.

Water is released.

Peptide bond

1 Substrates bind at active site. Enzyme changes shape to hold substrates in proper position.

2 Internal rearrangements leading to catalysis occur.

3 Product is released. Enzyme returns to original shape and is available to catalyze another reaction.

Active site

+


An enzyme’s substrate binds in the…

1) active site

2) catalyst

3) peptide bond

4) allosteric site


An enzyme works by…

1) speeding up reactions that would

have happened anyway

2) making reactions happen that would

not have otherwise happened


Figure 2.22 Structure of DNA.

Deoxyribose

sugar

Phosphate

Sugar-phosphate

backbone

Adenine nucleotide Hydrogen

bond

Thymine nucleotide

Phosphate Sugar:

Deoxyribose Phosphate Sugar Thymine (T) Base:

Adenine (A)

Adenine (A)

Thymine (T)

Cytosine (C)

Guanine (G)

(b)

(a)

(c) Computer-generated image of a DNA molecule


Figure 2.22a Structure of DNA.

Adenine nucleotide Thymine nucleotide

Phosphate

Sugar:

Deoxyribose

Phosphate Sugar Thymine (T)

Base:

Adenine (A)

(a)


Figure 2.22b Structure of DNA.

Deoxyribose

sugar Phosphate

Sugar-phosphate

backbone

Hydrogen bond

Adenine (A)

Thymine (T)

Cytosine (C)

Guanine (G)

(b)


Figure 2.23 Structure of ATP (adenosine triphosphate).

Adenosine triphosphate (ATP)

Adenosine diphosphate (ADP)

Adenosine monophosphate (AMP)

Adenosine

Adenine

Ribose

Phosphate groups

High-energy phosphate

bonds can be hydrolyzed

to release energy.


Figure 2.24a Three examples of cellular work driven by energy from ATP.

Solute

Membrane

protein

+

(a) Transport work: ATP phosphorylates transport

proteins, activating them to transport solutes

(ions, for example) across cell membranes.


Figure 2.24b Three examples of cellular work driven by energy from ATP.

Relaxed smooth muscle cell

Contracted smooth muscle cell

+

Mechanical work: ATP phosphorylates

contractile proteins in muscle cells so the

cells can shorten.

(b)


Figure 2.24c Three examples of cellular work driven by energy from ATP.

+

Chemical work: ATP phosphorylates key

reactants, providing energy to drive

energy-absorbing chemical reactions.

(c)


A nucleotide…

1) is the building block of nucleic acids

2) contains a pentose sugar

3) has a base (A, T, C, G, or U)

4) has a phosphate group

5) all of the above

human anatomy & physiology chapter 2: chemistry comes...

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