BIOL 235 Midterm 1-Version B Tips 2023
, Chap 1. -Positive feedback: Strengthen or reinforce a change in one of the body’s controlled
conditions. Control center provides a physiological response that adds to or reinforces the initial
change in the controlled condition—continues till interrupted by some mechanism. Frontal
plane: Divides the body into anterior (front) and posterior (back) portions.
Chap 2. -Water molecule bond: One atom of oxygen shares electrons with two atoms of
hydrogen. Polar covalent bond, sharing of electrons is unequal=nucleus of one atom attracts the
shared electrons more strongly than the nucleus of the other atom. Oxygen atom attracts the
electrons more strongly than the hydrogen atoms=oxygen atom has greater electronegativity.
*Inorganic compounds=structurally simple, water/salts/acids/bases, cannot be used by cells to
perform biological functions, carbon dioxide
Organic compounds – always contain carbon(carbon not easily dissolved in water, useful for
body structures), covalent bonds, large molecules. Carbs/lipids/proteins/ATP/nucleic acids.
They carry out complex functions within the body.
*Covalent bonds=can form between atoms of the same element, can be polar or non-polar,
forms when electrons are shared, and most common chemical bond in the body
*Atomic number of an element=proton # in nucleus
Mass number – protons plus neutrons
Isotopes – atoms that have the same number of protons but different numbers of neutrons
(different mass #) most are stable. If an atom is an isotope, its chemical properties remain the
same, this only changes if the electron number is different, as electrons determine chemical
properties of that element.
Atomic mass – amount of all naturally occurring isotopes.
Non-polar bond – a covalent bond where atoms share electrons equally
Polar bond – a covalent bond where atoms do not share electrons equally. One atom has more
electronegativity. (H20 is a polar covalent bond. O attracts electrons more)
Hydrogen bond – partially positive hydrogen attracts partially negative atoms. (usually O or
N) They result from attraction of positive and negative charges. They are weak. They help link
other molecules together.
Enzymes - Properties of enzymes: protein molecules that speed up chemical reactions in
organisms. They are catalysts, they decrease the amount of energy required for a reaction to
occur. Consist of two parts: (1) protein portion (apoenzyme), (2) non protein portion (cofactor).
Three properties: (1) Enzymes are highly specific (enzyme matched to particular substrate), (2)
Enzymes are very efficient, (3) Enzymes are subject to a variety of cellular controls. End in
‘ase’. ATPases split ATP. Proteases break down proteins.
*Fibrous proteins=form muscle fiber, tendons, connective tissue, and bone. (Actin, collagen,
dystrophin, elastin, keratin, myosin, tropomyosin, tubulin, and fibrin). Insoluble in water
*Globular proteins=more water soluble than other classes of proteins and they may have
several functions including transporting, catalyzing, and regulating. Hemoglobin, lipoproteins,
albumin, enzymes, antibodies.
, Chap 1. -Positive feedback: Strengthen or reinforce a change in one of the body’s controlled
conditions. Control center provides a physiological response that adds to or reinforces the initial
change in the controlled condition—continues till interrupted by some mechanism. Frontal
plane: Divides the body into anterior (front) and posterior (back) portions.
Chap 2. -Water molecule bond: One atom of oxygen shares electrons with two atoms of
hydrogen. Polar covalent bond, sharing of electrons is unequal=nucleus of one atom attracts the
shared electrons more strongly than the nucleus of the other atom. Oxygen atom attracts the
electrons more strongly than the hydrogen atoms=oxygen atom has greater electronegativity.
*Inorganic compounds=structurally simple, water/salts/acids/bases, cannot be used by cells to
perform biological functions, carbon dioxide
Organic compounds – always contain carbon(carbon not easily dissolved in water, useful for
body structures), covalent bonds, large molecules. Carbs/lipids/proteins/ATP/nucleic acids.
They carry out complex functions within the body.
*Covalent bonds=can form between atoms of the same element, can be polar or non-polar,
forms when electrons are shared, and most common chemical bond in the body
*Atomic number of an element=proton # in nucleus
Mass number – protons plus neutrons
Isotopes – atoms that have the same number of protons but different numbers of neutrons
(different mass #) most are stable. If an atom is an isotope, its chemical properties remain the
same, this only changes if the electron number is different, as electrons determine chemical
properties of that element.
Atomic mass – amount of all naturally occurring isotopes.
Non-polar bond – a covalent bond where atoms share electrons equally
Polar bond – a covalent bond where atoms do not share electrons equally. One atom has more
electronegativity. (H20 is a polar covalent bond. O attracts electrons more)
Hydrogen bond – partially positive hydrogen attracts partially negative atoms. (usually O or
N) They result from attraction of positive and negative charges. They are weak. They help link
other molecules together.
Enzymes - Properties of enzymes: protein molecules that speed up chemical reactions in
organisms. They are catalysts, they decrease the amount of energy required for a reaction to
occur. Consist of two parts: (1) protein portion (apoenzyme), (2) non protein portion (cofactor).
Three properties: (1) Enzymes are highly specific (enzyme matched to particular substrate), (2)
Enzymes are very efficient, (3) Enzymes are subject to a variety of cellular controls. End in
‘ase’. ATPases split ATP. Proteases break down proteins.
*Fibrous proteins=form muscle fiber, tendons, connective tissue, and bone. (Actin, collagen,
dystrophin, elastin, keratin, myosin, tropomyosin, tubulin, and fibrin). Insoluble in water
*Globular proteins=more water soluble than other classes of proteins and they may have
several functions including transporting, catalyzing, and regulating. Hemoglobin, lipoproteins,
albumin, enzymes, antibodies.
