Biochemical Concepts - AP Biology
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A promoter sequence is a stretch of DNA upstream of a gene that helps initiate transcription. Which base pairs, if any, would you expect to find in high proportions in promotor sequences?
A promoter sequence is a stretch of DNA upstream of a gene that helps initiate transcription. Which base pairs, if any, would you expect to find in high proportions in promotor sequences?
Promoters help the transcription machinery and associated proteins (like DNA helicase) find the correct spot to start transcription and facilitate opening of the DNA. When transcription takes place, DNA helicase must open up or "unzip" the double helix. Te fewer the hydrogen bonds the easier it is for DNA to be denatured. Adenine and thymine only have two hydrogen bonds between them, while cytosine and guanine have 3. Thymine and adenine are the best candidates for promoter sequences based on their fewer number of hydrogen bonds which is evidenced by a common promoter sequence called "TATA box".
Promoters help the transcription machinery and associated proteins (like DNA helicase) find the correct spot to start transcription and facilitate opening of the DNA. When transcription takes place, DNA helicase must open up or "unzip" the double helix. Te fewer the hydrogen bonds the easier it is for DNA to be denatured. Adenine and thymine only have two hydrogen bonds between them, while cytosine and guanine have 3. Thymine and adenine are the best candidates for promoter sequences based on their fewer number of hydrogen bonds which is evidenced by a common promoter sequence called "TATA box".
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Fat is composed of which of the following smaller molecules?
Fat is composed of which of the following smaller molecules?
Fat is made up of glycerol and fatty acids. Specifically, a fat is composed of three fatty acids chains—composed of 16 or 18 carbon atoms in length—connected to a glycerol by way of an ester linkage.
Fat is made up of glycerol and fatty acids. Specifically, a fat is composed of three fatty acids chains—composed of 16 or 18 carbon atoms in length—connected to a glycerol by way of an ester linkage.
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Which of the following best describes the composition of glycerol molecules?
Which of the following best describes the composition of glycerol molecules?
Glycerol is composed of an alcohol attached to three carbons each bearing a hydroxyl group.
Glycerol is composed of an alcohol attached to three carbons each bearing a hydroxyl group.
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Fatty acids vary in length and in the number and locations of double bonds between the carbon atoms. If there are no double bonds between the carbon atoms in the tail then the fatty acid is said to be __________.
Fatty acids vary in length and in the number and locations of double bonds between the carbon atoms. If there are no double bonds between the carbon atoms in the tail then the fatty acid is said to be __________.
A saturated fatty acid has no double bonds between the carbon atoms making up the tail of the fatty acid. This lack of double bonding allows for as many hydrogen atoms as possible to be bonded to the carbon skeleton, thus the fatty acid is said to be saturated with hydrogen atoms.
A saturated fatty acid has no double bonds between the carbon atoms making up the tail of the fatty acid. This lack of double bonding allows for as many hydrogen atoms as possible to be bonded to the carbon skeleton, thus the fatty acid is said to be saturated with hydrogen atoms.
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A fatty acid that has two double bonds between its carbon atoms is called __________.
A fatty acid that has two double bonds between its carbon atoms is called __________.
An unsaturated fatty acid has one or more double bonds in its hydrocarbon tail. These double bonds are formed by the removal of hydrogen atoms from the carbon tail, resulting in a kink in the tail. As such, they are not fully saturated with hydrogen atoms. Cholesterol is a type of lipid that contains four hydrocarbon rings in its structure. Hydrogenated fatty acids are unnatural saturated fatty acids that are modified for their physical properties.
An unsaturated fatty acid has one or more double bonds in its hydrocarbon tail. These double bonds are formed by the removal of hydrogen atoms from the carbon tail, resulting in a kink in the tail. As such, they are not fully saturated with hydrogen atoms. Cholesterol is a type of lipid that contains four hydrocarbon rings in its structure. Hydrogenated fatty acids are unnatural saturated fatty acids that are modified for their physical properties.
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Three fatty acids each joined to glycerol by an ester linkage is a __________.
Three fatty acids each joined to glycerol by an ester linkage is a __________.
A triacylglycerol (also called commonly referred to as a fat or a triglyceride) is composed of three fatty acid chains linked to glycerol via an ester linkage. The fatty acids can be the same or two or three different types. Steroids are derived from cholesterol, a molecule that contains four hydrocarbon rings attached together. Phospholipids only have two fatty acid tails linked to a glycerol head and a phosphate group.
A triacylglycerol (also called commonly referred to as a fat or a triglyceride) is composed of three fatty acid chains linked to glycerol via an ester linkage. The fatty acids can be the same or two or three different types. Steroids are derived from cholesterol, a molecule that contains four hydrocarbon rings attached together. Phospholipids only have two fatty acid tails linked to a glycerol head and a phosphate group.
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Which of the following is an example of a lipid?
Which of the following is an example of a lipid?
Triacylglycerol (also called a fat or triglyceride) is a type of lipid. Amino acids are the subunits that make up proteins. Chitin and cellulose are polysaccharides, or carbohydrates.
Triacylglycerol (also called a fat or triglyceride) is a type of lipid. Amino acids are the subunits that make up proteins. Chitin and cellulose are polysaccharides, or carbohydrates.
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Which of the following was not present in large amounts in Earth's early atmosphere?
Which of the following was not present in large amounts in Earth's early atmosphere?
Earth's early atmosphere contained carbon, 
(methane), 
(ammonia), and 
, but no oxygen.
Earth's early atmosphere contained carbon,
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Polymers of amino acids are called __________.
Polymers of amino acids are called __________.
Polymers of amino acids are called polypeptides. A protein is made up of one or more polypeptide chains that has folded and coiled in specific 3D configurations. Nucleic acids are polymers of nucleotides. Examples of nucleic acids are RNA and DNA. Ribosomes are the site of protein synthesis and are made of rRNA and protein.
Polymers of amino acids are called polypeptides. A protein is made up of one or more polypeptide chains that has folded and coiled in specific 3D configurations. Nucleic acids are polymers of nucleotides. Examples of nucleic acids are RNA and DNA. Ribosomes are the site of protein synthesis and are made of rRNA and protein.
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The unique three-dimensional shape of a protein is called its __________.
The unique three-dimensional shape of a protein is called its __________.
Conformation is the the term for the three dimensional structure of proteins. Though the types of proteins are incredibly diverse they are all polymers made up of the same set of 20 amino acids. A protein's molecular weight involves the sum of all the atoms and their abundances, molecular weight is often used to approximate the size of a protein when determining if it will pass through a pore or channel in a membrane. The amino acid sequence is the primary structure, and is held together by peptide bonds.
Conformation is the the term for the three dimensional structure of proteins. Though the types of proteins are incredibly diverse they are all polymers made up of the same set of 20 amino acids. A protein's molecular weight involves the sum of all the atoms and their abundances, molecular weight is often used to approximate the size of a protein when determining if it will pass through a pore or channel in a membrane. The amino acid sequence is the primary structure, and is held together by peptide bonds.
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How many naturally occurring amino acids are there?
How many naturally occurring amino acids are there?
All proteins are made up of amino acids. Even though proteins are highly diverse they all can be built from the same set of 20 amino acids. Thus, the order in which these amino acids are linked together (primary structure, which is directly determined by the DNA sequence) determines its structure and function.
All proteins are made up of amino acids. Even though proteins are highly diverse they all can be built from the same set of 20 amino acids. Thus, the order in which these amino acids are linked together (primary structure, which is directly determined by the DNA sequence) determines its structure and function.
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Amino acids possess both __________ and __________.
Amino acids possess both __________ and __________.
Amino acids are made up of carboxyl and amino groups. Hence their name, amino acids describes the functional groups found in all proteins, regardless of their R-groups. Carboxyl groups are also known as carboxylic acid groups. Glycerol is found in lipids, specifically fats where it is linked to fatty acid chains. Hydroxyl groups are also known as alcohol groups and are not present in all amino acids, although, some R-groups contain hydroxyl functional groups.
Amino acids are made up of carboxyl and amino groups. Hence their name, amino acids describes the functional groups found in all proteins, regardless of their R-groups. Carboxyl groups are also known as carboxylic acid groups. Glycerol is found in lipids, specifically fats where it is linked to fatty acid chains. Hydroxyl groups are also known as alcohol groups and are not present in all amino acids, although, some R-groups contain hydroxyl functional groups.
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The covalent bond that links two amino acids together is called __________.
The covalent bond that links two amino acids together is called __________.
The covalent bond between two amino acids is called a peptide bond. This is formed by positioning two amino acids so the carboxyl group of one is adjacent to the amino group of another. An enzyme then joins the two via a dehydration synthesis reaction. Ester bonds link fatty acids to glycerol heads, and phosphodiester bonds are formed between the sugar and phosphate backbone of a nucleic acid.
The covalent bond between two amino acids is called a peptide bond. This is formed by positioning two amino acids so the carboxyl group of one is adjacent to the amino group of another. An enzyme then joins the two via a dehydration synthesis reaction. Ester bonds link fatty acids to glycerol heads, and phosphodiester bonds are formed between the sugar and phosphate backbone of a nucleic acid.
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The unique sequence of amino acids in a protein is its __________.
The unique sequence of amino acids in a protein is its __________.
The primary structure of a protein is its amino acid sequence. The coils and folds of a protein are its secondary structure. Irregular contortions in the protein structure due to interactions between amino acid side chains is the tertiary structure. The overall structure when two or more polypeptides aggregated is the quaternary structure.
The primary structure of a protein is its amino acid sequence. The coils and folds of a protein are its secondary structure. Irregular contortions in the protein structure due to interactions between amino acid side chains is the tertiary structure. The overall structure when two or more polypeptides aggregated is the quaternary structure.
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Disulfide bonds may be formed in a protein's __________.
Disulfide bonds may be formed in a protein's __________.
Disulfide bonds may be formed in both tertiary and/or quaternary structures of a protein. These bonds result from the oxidation of the R-group (side chain) of the amino acid cysteine.
Disulfide bonds may be formed in both tertiary and/or quaternary structures of a protein. These bonds result from the oxidation of the R-group (side chain) of the amino acid cysteine.
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Which of the following terns best describes a molecule that contains three fatty acid chains bonded to a glycerol molecule?
Which of the following terns best describes a molecule that contains three fatty acid chains bonded to a glycerol molecule?
Structurally speaking, a triglyceride molecule contains three fatty acid chains covalently bonded to glycerol—specifically where the hydroxyl groups are located on the glycerol molecule.
Structurally speaking, a triglyceride molecule contains three fatty acid chains covalently bonded to glycerol—specifically where the hydroxyl groups are located on the glycerol molecule.
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Which of the following protein structures is determined by its amino acid sequence?
Which of the following protein structures is determined by its amino acid sequence?
The linear sequence of amino acids in a polypeptide chain gives rise to the protein's primary structure.
The linear sequence of amino acids in a polypeptide chain gives rise to the protein's primary structure.
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Which of the following is not true regarding RNA?
Which of the following is not true regarding RNA?
RNA stands for ribonucleic acid, and each RNA nucleotide contains one phosphate, one nitrogenous base (either adenine, uracil, cytosine, or guanine), and one ribose sugar. RNA does not contain a deoxyribose sugar as seen in DNA.
RNA stands for ribonucleic acid, and each RNA nucleotide contains one phosphate, one nitrogenous base (either adenine, uracil, cytosine, or guanine), and one ribose sugar. RNA does not contain a deoxyribose sugar as seen in DNA.
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At which level of protein structure does the formation of disulfide bridges occur?
At which level of protein structure does the formation of disulfide bridges occur?
The formation of disulfide bridge occurs in the tertiary and/or quaternary level of protein structure. This involves two sulfur atoms sharing a lone pair of electrons to form a covalent bond, which enhances the integrity of the protein's structure. The amino acid that is involved in forming disulfide bridges is cysteine.
The formation of disulfide bridge occurs in the tertiary and/or quaternary level of protein structure. This involves two sulfur atoms sharing a lone pair of electrons to form a covalent bond, which enhances the integrity of the protein's structure. The amino acid that is involved in forming disulfide bridges is cysteine.
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A polyunsaturated lipid contains which of the following that is/are not contained in saturated lipids?
A polyunsaturated lipid contains which of the following that is/are not contained in saturated lipids?
The term saturated when describing a lipid means that a molecule has the maximum number of hydrogens on its carbons, it is saturated with hydrogens. An unsaturated lipid has less than the maximum amount of hydrogens bonded to its carbons because there is a double bond between two of the carbons. Lipids molecules can have one carbon to carbon double bond (mono-unsaturated) or multiple (poly-unsaturated).
The term saturated when describing a lipid means that a molecule has the maximum number of hydrogens on its carbons, it is saturated with hydrogens. An unsaturated lipid has less than the maximum amount of hydrogens bonded to its carbons because there is a double bond between two of the carbons. Lipids molecules can have one carbon to carbon double bond (mono-unsaturated) or multiple (poly-unsaturated).
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