HUMAN SYSTEMS BIO 20 EXAM
QUESTIONS WITH COMPLETE
ANSWERS
Pyloric Sphincter - ANSWER-Muscular ring that acts as a valve between the
stomach and the duodenum ; controlling the passage of food out of stomach
Duodenum - ANSWER-The first 25 cm of the small intestine
Jejeumnum - ANSWER-Middle part of small intestine about 2.5 m long contains
more folds and secretory glands than the duodenum
Ileum - ANSWER-Is 3 m long the last part of the small intestine contains fewer
smaller vili it reabsorbs nutrients and push the remaining undigested material into the
large intestine
Gastrin - ANSWER-Stomach hormone that stimulates the secretion of hydrochloric
acid and the inactive precursor molecule of pepsin from glands in the stomach
Secretin - ANSWER-One of three enzymes( including CCK and GIP) secreted into
the bloodstream by the duodenum, causing inhibition of stomach movement and
secretions, and enabling fatty meals to remain in the stomach longer than non-fatty
meals; also stimulates the pancreas to release more bicarbonate to neutralize acidic
chime
GIP - ANSWER-Gastric inhibitory peptide; one of the three enzymes (including
secretin and CCK) secreted into the bloodstream by the duodenum causing inhibition
of stomach movement and secretions, enabling fatty meals to remain in the stomach
longer then non fatty meals
Biuret reagent - ANSWER-Test for proteins; has a blue colour that changes to violet
in presence of proteins or pink in presence of peptides
Iodine solution - ANSWER-Test for starch; turns brownish colour to blue-black in
presence of starch
Benedict's Solution - ANSWER-Test for sugars; sugars react with this solution after
being heated in a boiling water bath. Increasing concentrations of sugar give a
continuum of colours
Enzyme - ANSWER-Protein molecule that acts as a catalyst to increase the rate of a
reaction
Vitamins and minerals - ANSWER-Are not macromolecules, but are essential to the
structures and functions of all cells
, Vili - ANSWER-Finger-like projection along the ridges of the small intestine;
increases surface area to aid in the absorption of nutrients
Microvili - ANSWER-Microscopic projection found along exposed cell surfaces that
greatly increases the surface area of the cell; found on the vili of the small intestine
and on the membranes of certain cells
Carbohydrases - ANSWER-An enzyme that digests carbohydrates
Lipases - ANSWER-An enzyme that digests fats
Proteases - ANSWER-An enzyme that digests larger polypeptides
Nucleases - ANSWER-An enzyme that digests nucleic acids
Segmentation - ANSWER-A process by which some physical digestion occurs in the
small intestine; chyme sloshes back and forth between segments of the small
intestine that forms when bands of circular muscle briefly contract
Hydrolysis - ANSWER-Chemical reaction in which the addition of a water molecule
cleaves a macromolecule into subunits; one hydrogen atom from water is attached to
one subunit and a hydroxyl group is bonded to the other subunit, breaking a covalent
bond in the macromolecule
Carbohydrates - ANSWER-Organic macromolecule that contains carbon, hydrogen,
and oxygen in a 1:2:1 ratio; ex include monosaccharides, disaccharides, and
polysaccharides
Lipid - ANSWER-Group of organic macromolecules, including fats, oils,
phospholipids, and steroids, that is insoluble in water, but soluble in a non-polar
organic substance
Nucleic acids - ANSWER-Macromolecules formed from a long chain of nucleotide
subunits, each consisting of a 5 carbon simple sugar, a nitrogen-containing base,
and a phosphate group; two types include DNA and RNA
Nucleotide - ANSWER-Units making up nucleic acids
Protein - ANSWER-Organic macromolecules assembled from subunits of amino
acids
Peptide bond - ANSWER-Bond between the amino group of one amino acid and the
carboxyl group of another in a protein
Pepsin - ANSWER-A Protein digesting enzyme secreted in the stomach; remains
inactive until hydrochloric acid is present
Amino acid - ANSWER-An organic compound consisting of a carboxylic acid group ,
and amino group and any various side groups linked together by peptide bonds to
form proteins
QUESTIONS WITH COMPLETE
ANSWERS
Pyloric Sphincter - ANSWER-Muscular ring that acts as a valve between the
stomach and the duodenum ; controlling the passage of food out of stomach
Duodenum - ANSWER-The first 25 cm of the small intestine
Jejeumnum - ANSWER-Middle part of small intestine about 2.5 m long contains
more folds and secretory glands than the duodenum
Ileum - ANSWER-Is 3 m long the last part of the small intestine contains fewer
smaller vili it reabsorbs nutrients and push the remaining undigested material into the
large intestine
Gastrin - ANSWER-Stomach hormone that stimulates the secretion of hydrochloric
acid and the inactive precursor molecule of pepsin from glands in the stomach
Secretin - ANSWER-One of three enzymes( including CCK and GIP) secreted into
the bloodstream by the duodenum, causing inhibition of stomach movement and
secretions, and enabling fatty meals to remain in the stomach longer than non-fatty
meals; also stimulates the pancreas to release more bicarbonate to neutralize acidic
chime
GIP - ANSWER-Gastric inhibitory peptide; one of the three enzymes (including
secretin and CCK) secreted into the bloodstream by the duodenum causing inhibition
of stomach movement and secretions, enabling fatty meals to remain in the stomach
longer then non fatty meals
Biuret reagent - ANSWER-Test for proteins; has a blue colour that changes to violet
in presence of proteins or pink in presence of peptides
Iodine solution - ANSWER-Test for starch; turns brownish colour to blue-black in
presence of starch
Benedict's Solution - ANSWER-Test for sugars; sugars react with this solution after
being heated in a boiling water bath. Increasing concentrations of sugar give a
continuum of colours
Enzyme - ANSWER-Protein molecule that acts as a catalyst to increase the rate of a
reaction
Vitamins and minerals - ANSWER-Are not macromolecules, but are essential to the
structures and functions of all cells
, Vili - ANSWER-Finger-like projection along the ridges of the small intestine;
increases surface area to aid in the absorption of nutrients
Microvili - ANSWER-Microscopic projection found along exposed cell surfaces that
greatly increases the surface area of the cell; found on the vili of the small intestine
and on the membranes of certain cells
Carbohydrases - ANSWER-An enzyme that digests carbohydrates
Lipases - ANSWER-An enzyme that digests fats
Proteases - ANSWER-An enzyme that digests larger polypeptides
Nucleases - ANSWER-An enzyme that digests nucleic acids
Segmentation - ANSWER-A process by which some physical digestion occurs in the
small intestine; chyme sloshes back and forth between segments of the small
intestine that forms when bands of circular muscle briefly contract
Hydrolysis - ANSWER-Chemical reaction in which the addition of a water molecule
cleaves a macromolecule into subunits; one hydrogen atom from water is attached to
one subunit and a hydroxyl group is bonded to the other subunit, breaking a covalent
bond in the macromolecule
Carbohydrates - ANSWER-Organic macromolecule that contains carbon, hydrogen,
and oxygen in a 1:2:1 ratio; ex include monosaccharides, disaccharides, and
polysaccharides
Lipid - ANSWER-Group of organic macromolecules, including fats, oils,
phospholipids, and steroids, that is insoluble in water, but soluble in a non-polar
organic substance
Nucleic acids - ANSWER-Macromolecules formed from a long chain of nucleotide
subunits, each consisting of a 5 carbon simple sugar, a nitrogen-containing base,
and a phosphate group; two types include DNA and RNA
Nucleotide - ANSWER-Units making up nucleic acids
Protein - ANSWER-Organic macromolecules assembled from subunits of amino
acids
Peptide bond - ANSWER-Bond between the amino group of one amino acid and the
carboxyl group of another in a protein
Pepsin - ANSWER-A Protein digesting enzyme secreted in the stomach; remains
inactive until hydrochloric acid is present
Amino acid - ANSWER-An organic compound consisting of a carboxylic acid group ,
and amino group and any various side groups linked together by peptide bonds to
form proteins
