Bio Midterm Chapter 2

What is an element?

Are pure substances, each consisting only of atoms with the same number of protons in their nucleus

What is an atom?

The smallest unit of matter

What are the components of an atom?

Protons, neutrons, electrons

What are the charges of a proton, neutron, and electron?

Protons are positively charged, neutrons neutral subatomic particle, electrons negatively charged; protons and neutrons make up the nucleus of the atom, electrons can be found in the orbital

What does it mean when an atom is neutral?

No net electrical charge

What does it mean when an atom is positively or negatively charged?

It is an ion

What are chemical bonds?

A strong attractive force that arises between two atoms, and the interaction unites the atoms into a molecule

What is the pH of a solution?

The measurement of the amount of hydrogen ions

What would cause the pH of a solution to become more acidic or basic?

Increasing the concentration of hydrogen ions (H+), more basic (alkaline) by increasing the concentration of hydroxide ions (OH-)

How does the H+ ion concentration affect the pH of a solution?

As the H+ concentration increases, the pH decreases (becoming more acidic); as the H+ concentration decreases, the pH increases (becoming more basic)

What are the pH ranges for an acidic, basic, or neutral solution?

Acidic solutions have a pH less than 7, neutral solutions are exactly 7, basic (alkaline) solutions have a pH greater than 7

Describe the structure and function of carbohydrates

Molecule that consists primarily of carbon, hydrogen, and oxygen atoms in a ratio of approximately 1:2:1; provide quick fuel (glucose), long-term energy storage; (starch/glycogen), and structural support (cellulose/chitin)

What are the monomers and polymers of carbohydrates?

Monosaccharides and polysaccharides

What are some monosaccharide and polysaccharide examples?

M = glucose, fructose P = starch, cellulose

Describe the characteristics of the following polysaccharides: glycogen, cellulose, starch

Glycogen = a polysaccharide that consists of highly branched chains of glucose monomers; cellulose = tough, insoluble polysaccharide; starch = a polysaccharide in which the bonding pattern between glucose monomers makes a chain that coils up into a spiral

Describe the structure and function of lipids

They are diverse, hydrophobic organic compounds composed of carbon, hydrogen, and oxygen, including fats, phospholipids, and steroids; their main functions include long-term energy storage, forming the structural lipid bilayer of cell membranes, signaling as hormones, and providing insulation

What are the general properties of fatty acids?

Lipid that consists of a (hydrophilic) car-boxyl group “head” and a (hydrophobic) “tail”

How do the properties of fatty acids contribute to the phospholipid bilayer?

These properties allow phospholipids to form spontaneous, fluid bilayers in water, where hydrophobic tails face inward, regulating membrane fluidity, permeability, and structural stability

What is the differences in structure and function of saturated and unsaturated fats?

Saturated fatty acids have only single bonds linking the carbons in their tails, their carbon chains are fully saturated with hydrogen atoms; an unsaturated fatty acid has at least one double bond between carbons making up its tail

What are some food sources of saturated fats?

Butter, lard, animal products, coconut oil, full fat daily

What are some food sources of unsaturated fats?

Fatty fish, olive oil, nuts, avocados, seeds

What is the structure and function of a triglyceride?

A lipid with three fatty acid tails bonded to a glycerol backbone, a fat; the function is energy storage

What is the major structure and function of a phospholipid?

Lipid with two (hydrophobic) fatty acid tails and a (hydrophilic) head that contains a phosphate group; the function is to create a selectively permeable barrier, maintaining membrane fluidity

Describe the structure and function of proteins

An organic (contains carbon and hydrogen) molecule that consists of one or more chains of amino acids folded up into a specific shape, proteins fold 4 times; catalyzing reactions (enzymes), structural support

What are the monomers of proteins?

Amino acids

What are the polymers of proteins?

Polypeptide

What are the components of an amino acid?

Consists of car-boxyl group, an amine group, and one of 20 R groups, all bonded to the same carbon atom

Which component determines the amino acid type?

The “R” group

What bonds are found between the amino acids within a polypeptide?

The peptide bond (covalent)

What is the function enzymes?

Organic molecules (protein or RNA) that speeds up a reaction without being changed / consumed by it

Describe the structure and function of nucleic acids

Nucleotides are small organic molecules that function as enzyme helpers, chemical messengers, and subunits of DNA and RNA, each consists of a monosaccharide bonded to a nitrogen - containing base and one, two, or three phosphate groups

What are monomers of nucleic acids?

A nucleotide

What is the function of nucleic acids?

Store, transmit, and express genetic information