Download B-2.8 Explain the factors that affect the rates of biochemical

B-2.8
Explain the factors that affect the rates of biochemical
reactions (including pH,temperature)
What you should know:
 Chemical reactions occur when reactants collide with each other. The amount of energy
needed to make this happen is the activation energy.
o Sometimes a chemical reaction must absorb energy
o Sometimes a chemical reaction must release energy
 Changes in temperature can affect a chemical reaction.
 pH (a measure of the acidity) must be kept the same. Buffers in an organism help maintain
the pH.
 A catalyst is speeds up a reaction by lowering the activation energy. Enzymes are proteins
that act as catalysts.
○ Enzymes are shape specific. Each particular enzyme can fit with only one reactant
(substrate).
○ Enzymes can be denatured (change shape) by changes in temperature and pH
Types of Questions they might ask:
 Explain how temperature, pH, and enzymes affect chemical reactions in living systems.
 interpret diagrams, charts, and graphs of biochemical reactions;
 Know the purpose of a catalyst.
B-3.4
Summarize how the structures of organic molecules
(including proteins, carbohydrates, and fats) are related to
their relative caloric values.
What you should know:
 Proteins are chains of amino acids.
○ made of carbon, hydrogen, oxygen, nitrogen
○ 4 Cal/gram.
 Carbohydrates (sugars and starches) are made of carbon, hydrogen, and oxygen.
○ simple sugars are monosaccharides – one sugar - such as glucose.
○ complex carbohydrates are disaccharides – two sugars – or polysaccharides – 3 or more
sugars – such as starch or cellulose.
○ they are the main source of energy
○ 4 Cal/gram
 Lipids, or fats, are made of carbon, hydrogen, and oxygen.
○ Lipid have two parts (glycerol and fatty acids)
○ Fats are stored energy.
○ 9 Cal/gram
Assessment Guidelines:
 recall the basic components of each type of organic molecule;
 compare the structure and calories of proteins, carbohydrates, and fats.
B-3.5
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Summarize the functions of proteins, carbohydrates, and
fats in the human body.
Proteins are involved in almost every function in the human body. For example, they serve
as the basis for structures, transport substances, regulate processes, speed up chemical
reactions, and control growth. .
○ Because of their structures, proteins serve different functions. For example,
 Structural proteins are used for support such as connective tissue and keratin that
forms hair and finger nails.
 Transport proteins transport many substances throughout the body such as
hemoglobin which transports oxygen from the lungs to the other parts of the body to
be used by cells in cellular respiration.
 Hormone proteins coordinate body activities such as insulin which regulates the
amount of sugar in the blood.
 Enzymes accelerate the speed of chemical reactions such as digestive enzymes which
break down food in the digestive tract.
Carbohydrates are important as an energy source for all organisms and as a structural
molecule in many organisms.
○ Some carbohydrates (such as cellulose) are used as structural material in plants.
Fats (lipids) are important to organisms for energy when carbohydrates are scarce since they
are the primary way to store energy.
○ Fats serve a variety of functions in humans, such as providing long-term energy storage,
cushioning of vital organs, and insulation for the body.
○ Fats also serve as a major component of cell membranes and are one of the raw materials
necessary for the production of some vitamins and hormones.
Assessment Guidelines:
 recall or compare the functions of each organic molecule.