Biology test

Ovalbumin is a protein found in eggs. Which of the following best describes the molecular structure of ovalbumin? -a group of six carbon atoms joined in a ring -a chain of amino acids folded and twisted into a molecule -a set of three fatty acids attached to a molecule of glycerol -a sequence of nitrogenous bases attached to a sugar-phosphate backbone

a chain of amino acids folded and twisted into a molecule

Which of the following best describes the composition of a nucleotide? -a pair of six-carbon rings attached to each other -a carbon atom joined to hydrogen and three functional groups -a chain of carbon atoms with a carboxyl group bonded to one end -a five-carbon sugar attached to a phosphate group and a nitrogenous base

a five-carbon sugar attached to a phosphate group and a nitrogenous base

Which of the following categories of organic molecules is correctly paired with one of its functions? -nucleic acids—digest dead cells -lipids—give quick energy to cells -carbohydrates—store genetic information -proteins—provide structure in skin, hair, and nails

proteins—provide structure in skin, hair, and nails

The role of an enzyme in a chemical reaction is to change which of the following? -the type of reaction -the activation energy of the reaction -the pH at which the reaction occurs -the temperature at which the reaction occurs

the activation energy of the reaction

Which of the following will most likely change when an enzyme is added to a reaction? -the pH of the reaction -the rate of the reaction -the products of the reaction -the temperature of the reaction

the rate of the reaction

Vitamin D is an organic molecule that regulates the absorption of calcium by the body. Which of the following elements is most common in a molecule of vitamin D? -aluminum -carbon -magnesium -sodium

Carbon

Which element is the main component of all organic molecules? -carbon -nitrogen -potassium -sodium

Carbon

Which of the following is the main reason that humans need to include carbohydrates in their diet? - carbohydrates are the building blocks for the cell growth and repair -carbohydrates act as catalysts to speed up chemical reactions -carbohydrates are broken down in cells for energy -carbohydrates combine to form many different proteins

-carbohydrates are broken down in cells for energy Clue: carbohy, carbs, sugar, energy -amino acids combine to form many different proteins -enzyme act as catalyst to speed up chemical reactions - proteins are building blocks for cell growth and repair

Many enzymes are found in the cytoplasm of human body cells. These enzymes would be expected to function optimally at which of the following temperatures and pH values? -0°C and pH 2 -12°C and pH 5 -37°C and pH 7 -80°C and pH 10

12°C and pH 5

Acetylcholine is an important chemical signal in the nervous system. Once acetylcholine is released, it is quickly broken down into other chemicals because of the activity of cholinesterase. Cholinesterase is which of the following? -a hormone -a lipid -an enzyme -an organelle

An enzyme

In red blood cells, the compound carbonic anhydrase increases the rate at which carbon dioxide is converted to bicarbonate ions for transport in the blood. In red blood cells, carbonic anhydrase acts as which of the following? -an enzyme -a hormone -a lipid -a sugar

An enzyme

Some bacteria contain a substance called nitrogenase. Nitrogenase catalyzes the chemical reaction that converts atmospheric nitrogen (N2) into ammonia (NH3). Nitrogenase is an example of which of the following? -a sugar -an enzyme -a nucleotide -an amino acid

An enzyme

Which of the following roles does an enzyme play when the body processes sucrose (table sugar) into glucose and fructose? -An enzyme decreases the body's need for sucrose. -An enzyme increases the amount of sucrose available. -An enzyme increases the rate at which the sucrose breaks down. -An enzyme decreases the amount of fructose and glucose product available.

An enzyme increases the rate at which the sucrose breaks down.

A student is preparing to run in a school track competition. For the quickest source of energy, the student should eat a food that contains a high percentage of -carbohydrates. -fat. -proteins. -sodium.

Carbohydrates

Cellulose is a compound found in plants. It is made of a long chain of molecules with ringed structures. The molecules contain mostly carbon, hydrogen, and oxygen atoms in a ratio of approximately 1 carbon : 2 hydrogen : 1 oxygen. To which category of biological molecules does cellulose belong? -carbohydrates -nucleic acids -phospholipids -proteins

Carbohydrates

Fructose, sucrose, and starch are all examples of -carbohydrates. -lipids. -nucleic acids. -proteins.

Carbohydrates

Salivary amylase breaks down which class of organic molecules? -carbohydrates -lipids -nucleic acids -proteins

Carbohydrates

Which of the following is the main reason that humans need to include carbohydrates in their diet? -Carbohydrates are broken down in cells for energy. -Carbohydrates combine to form many different proteins. -Carbohydrates act as catalysts to speed up chemical reactions. -Carbohydrates are the building blocks for cell growth and repair.

Carbohydrates are broken down in cells for energy.

If scientists search other planets for possible life, they are likely to focus on the presence of molecules containing which of the following elements? - carbon - iron -potassium -sodium

Carbon

Scientists have found geysers on one of Saturn's moons. The geysers release water vapor containing complex organic compounds, which may indicate the presence of life. Which of the following elements is most likely abundant in the organic compounds in the water vapor? -carbon -chlorine -iron -zinc

Carbon

The body structure of a reef-building coral consists of a hard skeleton covering soft tissue. Which of the following elements is most common in the coral's soft tissue? -carbon -chlorine -sodium -zinc

Carbon

Scientists have found geysers on one of Saturn's moons. The geysers release water vapor containing complex ORGANIC COMPOUNDS, which may indicate the presence of life. which of the following elements is most likely abundant in the organic compounds in the water vapor? - carbon -chlorine -iron -zinc

Carbon Clue; organic compound contains carbon

Cellulose is a complex carbohydrate that makes up the cell walls of plants. Which of the following elements are main components of cellulose? - calcium and chlorine -carbon and hydrogen -potassium and chlorine -sodium and hydrogen

Carbon and hydrogen

Peptidoglycan is a compound in the cell walls of many bacteria. Which of the following elements are most abundant in peptidoglycan? -aluminum and sodium -carbon and hydrogen -chlorine and iron -iodine and potassium

Carbon and hydrogen

Cellulose is a complex carbohydrate that makes up the cell walls of plants. which of the following elements are main components of cellulose? -calcium and Chlorine -carbon and hydrogen -potassium and chlorine -sodium and hydrogen

Carbon and hydrogen Clue: cellulOSE & CARBOHYdrates are sugar

Lemurs' bodies are adapted to efficiently store energy for times when food is scarce. This adaptation may help to explain how lemur ancestors survived the trip across the Mozambique Channel from mainland Africa to Madagascar. Which of the following types of molecules are primarily used for long-term energy storage in the lemur? -lipids -monosaccharides -nucleic acids -proteins

Lipids

One category of organic compounds contains molecules composed of long hydrocarbon chains. The hydrocarbon chains may be saturated or unsaturated. Which of the following categories of organic compounds contains these molecules? -carbohydrates -lipids -nucleic acids -proteins

Lipids

An amoeba in a pond engulfs and consumes a paramecium. The amoeba uses which of the following to quickly break down the organic molecules in the paramecium? -enzymes -glucose -polysaccharides -water

Enzymes

Baby food manufacturers sometimes use proteases in their products. Proteases catalyze the breakdown of the proteins in these foods, making digestion easier for infants. Proteases are which of the following types of molecules? -enzymes -fatty acids -hormones -monosaccharides

Enzymes

Fatty acids are one of the products that result from the action of lipase in the digestive system. What is one way that fatty acids are used in the body? -for storing energy -for encoding genetic information -as the building blocks of antibodies -as the building blocks of hemoglobin

For storing energy

Which group of organic compounds contains fatty acids? -carbohydrates -lipids -nucleic acids -proteins

Lipids

Which of the following elements is most common in the tissues of plants? -hydrogen -iron -potassium -sodium

Hydrogen

Many plants have waxy coatings on some surfaces. This coating reduces water loss because it is not water-permeable. This waxy coating is which of the following types of organic molecule? -carbohydrate -lipid -nucleic acid -protein

Lipid

Which type of molecule in the yolk of a chicken egg provides the most energy for a developing chick? -lipid -nucleic acid -salt -water

Lipid

Many land plants store energy in starch. When energy is needed, the starch molecules can be broken down quickly. This chemical reaction produces which of the following? -amino acids -lipids -monosaccharides - RNA chains

Monosaccharides

When lactose is digested by the human body, each lactose molecule is broken down into smaller molecules. To which of the following categories of molecules do these smaller molecules belong? - amino acids - monosaccharides -nucleic acids -polypeptides

Monosaccharides

When lactOSE is digested by the human body, each lactose molecule is broken down into smaller molecules. To which of the following categories of molecules do these smaller molecules belong? - amino acids - monosaccharides - nucleic acids - polypetides

Monosaccharides Clue: lactOSE means sugar and mono means sugar -Amino acids are building blocks of protein -polypeptides are proteins -nucleic acids are DNA or RNA

Resistance to antibiotics results from variations in the genetic code of Streptococcus pneumoniae. Which type of molecule encodes genetic information in Streptococcus pneumoniae? -carbohydrate -fatty acid -nucleic acid -protein

Nucleic acid

Many farm animals eat hay, which is made by cutting and drying plants such as ryegrass and timothy grass. Scientists analyzed the composition of hay after it was cut and again after it was dried. The amounts of which common biological elements would have decreased the most as the hay dried? -sulfur and calcium -phosphorus and zinc -oxygen and hydrogen -nitrogen and chlorine

Oxygen and hydrogen

In the human body, fibrinogen is necessary for sealing cuts and stopping the loss of blood. Since fibrinogen is made of chains of amino acids, it is an example of which type of organic molecule? -carbohydrate -protein -fatty acid -nucleic acid

Protein

97% of all living things are made of what?

S- sulfur P- phosphorous O- oxygen N- nitrogen C- carbon H- hydrogen

Which of the following statements best describes an effect of pH on the functioning of salivary amylase? -Salivary amylase functions most effectively at a pH of about 4. -Salivary amylase functions most effectively at a pH of about 7. -Salivary amylase cannot break down starch into maltose at pH values less than 7. -Salivary amylase breaks down protein instead of starch at pH values greater than 9.

Salivary amylase functions most effectively at a pH of about 7.

Some bacteria live in hot springs. Their cells contain enzymes that function best at temperatures of 70°C or higher. At a temperature of 50°C, how will the enzymes in these bacterial cells most likely be affected? -The enzymes will be destroyed by lysosomes. -The enzymes will lose their bond structure and fall apart. -The enzymes will require less energy to function than at 70°C. -The enzymes will not increase the rate of reactions as much as they would at 70°C.

The enzymes will not increase the rate of reactions as much as they would at 70°C.

Which of the following best explains why enzymes are necessary for many cellular reactions? -Enzymes supply the oxygen necessary for the reactions. -Enzymes change reactants from solid to liquid during the reactions. -The reactions take up too much space in the cell if enzymes are missing. -The reactions are too slow to meet the needs of the cell if enzymes are missing.

The reactions are too slow to meet the needs of the cell if enzymes are missing

What do disaccarides, such as sucrose, and polysaccharides, such as starch, have in common? - they are lipids made of fatty acids -they are proteins made of amino acids -they are nucleic acids made of nucleotides -they are carbohydrates made of simple sugars

They are CARBOHYdrates made of simple SUGARS Clue: the word disaccharides and polysaccharides mean sugar, sucrOSE and starch are both sugars

What do disaccharides, such as sucrose, and polysaccharides, such as starch, have in common? -They are lipids made of fatty acids. -They are proteins made of amino acids. -They are nucleic acids made of nucleotides. -They are carbohydrates made of simple sugars.

They are carbohydrates made of simple sugars

Cellular respiration involves a series of chemical reactions. Which of the following is a primary way that enzymes affect these reactions? -They decrease the pH of the products. -They increases the rate of the reactions. -They take the place of oxygen as a reactant. -They change the location of the reactions in the cell.

They increase the rate of reactions

A scientist is analyzing a sample of tissue from a plant. Which of the following elements will be most abundant in the sample? -zinc and copper -sodium and chlorine -carbon and hydrogen -magnesium and calcium

carbon and hydrogen

Scientists hypothesize that the microscopic organisms inside a termite's gut are responsible for breaking down the wood that the termite eats. To support this hypothesis, research results should show that the microscopic organisms can produce which of the following? -ATP -polysaccharides -enzymes specific to cellulose -nucleic acids that are double-stranded

enzymes specific to cellulose