Attributes of Life
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Biology › Attributes of Life
What makes up the tertiary structure of a protein?
The folding caused by interactions between R groups of various amino acids in the same polypeptide chain
Disulfide bonds between two valine amino acids
Covalent bonds that occur between R groups with a positive charge and R groups with a negative charge
Carbon bonds between R groups with a positive charge and R groups with a negative charge
Explanation
The tertiary structure of a protein is created by various interactions between the R groups in the chain. This makes the protein fold three-dimensionally.
One example would be ionic bonds forming between a positively charged R group and a negatively charged R group. Covalent disulfide bonds will create a tertiary shape between two cysteine amino acids. Hydrophobic R groups will also contribute to the structure, bending toward one another to avoid contact with the aqueous environment.
Which of the following properties of water is most responsible for the fact that lakes do not freeze from the bottom up?
The density of ice is less than the density of liquid water
Hydrogen bonding between water molecules gives water a high boiling point
Water freezes at
Water has high surface tension
Explanation
When water freezes, its density decreases (most substances do not exhibit this property). This means that ice will float on top of a lake, rather than sink to the bottom. Because the ice floats on top of a lake, it freezes from the top down rather than from the bottom up. The other answer choices are all properties of water, but they do not explain why lakes freeze from top down, and not from bottom up.
What makes up the tertiary structure of a protein?
The folding caused by interactions between R groups of various amino acids in the same polypeptide chain
Disulfide bonds between two valine amino acids
Covalent bonds that occur between R groups with a positive charge and R groups with a negative charge
Carbon bonds between R groups with a positive charge and R groups with a negative charge
Explanation
The tertiary structure of a protein is created by various interactions between the R groups in the chain. This makes the protein fold three-dimensionally.
One example would be ionic bonds forming between a positively charged R group and a negatively charged R group. Covalent disulfide bonds will create a tertiary shape between two cysteine amino acids. Hydrophobic R groups will also contribute to the structure, bending toward one another to avoid contact with the aqueous environment.
Which of the following properties of water is most responsible for the fact that lakes do not freeze from the bottom up?
The density of ice is less than the density of liquid water
Hydrogen bonding between water molecules gives water a high boiling point
Water freezes at
Water has high surface tension
Explanation
When water freezes, its density decreases (most substances do not exhibit this property). This means that ice will float on top of a lake, rather than sink to the bottom. Because the ice floats on top of a lake, it freezes from the top down rather than from the bottom up. The other answer choices are all properties of water, but they do not explain why lakes freeze from top down, and not from bottom up.
How do amino acids connect to make a protein?
The carbon atom of the carboxyl group bonds with the nitrogen atom of the amine group through a dehydration synthesis reaction
Hydroxide binds with hydrogen between the alcohol group and the carboxyl group through a hydration synthesis reaction
Hydrogen is added to atoms of carbon, forming kinks at the double bonds
A peptide bond is formed between the ketone group of one amino acid and the nitrogen group of another amino acid
Explanation
Proteins are synthesized through dehydration synthesis reactions, which is the removal of water between two amino acids. In this case, two hydrogen atoms are removed from the amine group and one oxygen is removed from the carboxyl group, forming a peptide bond between the carbon atom of one amino acid and the nitrogen atom of the other amino acid.
Proteins are extremely important to biological function and metabolism. Amino acids are the monomers that make up proteins. What elements can be found in amino acids?
Carbon, oxygen, hydrogen, nitrogen, and sulfur
Carbon, hydrogen, and oxygen
Carbon, hydrogen, and nitrogen
Carbon, hydrogen, oxygen, and phosphorous
Explanation
All amino acids contain carbon, hydrogen, oxygen, and nitrogen. These elements create a carboxylic acid group and an amine group, which can fuse to form a peptide bond. Peptide bonds hold amino acids together and generate the primary structure of the protein.
Cysteine, a specific amino acid, also contains sulfur. Thus, the correct answer is that carbon, oxygen, hydrogen, nitrogen, and sulfur can all be found in amino acids.
Phosphorus is never found in amino acids, but plays an important role in the structure of nucleic acids, such as DNA, and in the modification and activation of proteins.
How do amino acids connect to make a protein?
The carbon atom of the carboxyl group bonds with the nitrogen atom of the amine group through a dehydration synthesis reaction
Hydroxide binds with hydrogen between the alcohol group and the carboxyl group through a hydration synthesis reaction
Hydrogen is added to atoms of carbon, forming kinks at the double bonds
A peptide bond is formed between the ketone group of one amino acid and the nitrogen group of another amino acid
Explanation
Proteins are synthesized through dehydration synthesis reactions, which is the removal of water between two amino acids. In this case, two hydrogen atoms are removed from the amine group and one oxygen is removed from the carboxyl group, forming a peptide bond between the carbon atom of one amino acid and the nitrogen atom of the other amino acid.
Which of the following biological macromolecules is incorrectly paired with its function in animal cells?
All of the biological macromolecules are correctly paired with their functions in animal cells
Lipids functions include biological membranes, cell signaling, and energy storage
Protein functions include receptors, cell signaling, enzymes, and cell structure
Carbohydrates functions include cell signalling, energy storage, and building blocks for nucleotides
DNA functions include storage of genetic information, as well as instructions and control of protein synthesis
Explanation
The four basic biological macromolecules carry out virtually every metabolic process of living organisms. Keep in mind that these molecules work together to achieve common goals. For example, enzymes (proteins) are used to help break down glucose (carbohydrate) in glycolysis. One product of glycolysis is energy in the form of ATP. ATP can be used to polymerize nucleotides (nucleic acids) to copy DNA.
The functions of specific types of macromolecules are highly dependent on their structures. For example, firbous proteins are used to provide structural support, while globular proteins are better suited to catalyze reactions as enzymes. The variety of macromolecular structures is directly related to the multitude of functions these molecules can facilitate.
Which of the following biological macromolecules is incorrectly paired with its function in animal cells?
All of the biological macromolecules are correctly paired with their functions in animal cells
Lipids functions include biological membranes, cell signaling, and energy storage
Protein functions include receptors, cell signaling, enzymes, and cell structure
Carbohydrates functions include cell signalling, energy storage, and building blocks for nucleotides
DNA functions include storage of genetic information, as well as instructions and control of protein synthesis
Explanation
The four basic biological macromolecules carry out virtually every metabolic process of living organisms. Keep in mind that these molecules work together to achieve common goals. For example, enzymes (proteins) are used to help break down glucose (carbohydrate) in glycolysis. One product of glycolysis is energy in the form of ATP. ATP can be used to polymerize nucleotides (nucleic acids) to copy DNA.
The functions of specific types of macromolecules are highly dependent on their structures. For example, firbous proteins are used to provide structural support, while globular proteins are better suited to catalyze reactions as enzymes. The variety of macromolecular structures is directly related to the multitude of functions these molecules can facilitate.
Proteins are extremely important to biological function and metabolism. Amino acids are the monomers that make up proteins. What elements can be found in amino acids?
Carbon, oxygen, hydrogen, nitrogen, and sulfur
Carbon, hydrogen, and oxygen
Carbon, hydrogen, and nitrogen
Carbon, hydrogen, oxygen, and phosphorous
Explanation
All amino acids contain carbon, hydrogen, oxygen, and nitrogen. These elements create a carboxylic acid group and an amine group, which can fuse to form a peptide bond. Peptide bonds hold amino acids together and generate the primary structure of the protein.
Cysteine, a specific amino acid, also contains sulfur. Thus, the correct answer is that carbon, oxygen, hydrogen, nitrogen, and sulfur can all be found in amino acids.
Phosphorus is never found in amino acids, but plays an important role in the structure of nucleic acids, such as DNA, and in the modification and activation of proteins.