Central Dogma of Molecular Biology

What three ways R-groups can differ?

R-groups can vary in their size, shape and polarity.

What determines a protein's primary structure ?

The unique amino acid sequence is a protein's primary structure.

What are the monomers of nucleic acids?

A gene is a segment of DNA that codes for a specific sequence of mRNA that is translated to pleotides. RNA is composed of ribonucleotides.

Which component of the nucleotide is at the 5' end of the nucleic acid? 3'?

A phosphate group is on the 5 prime end of a nucleic acid, and the sugar is on the 3 prime end.

What is a polypeptide?

Amino acids link via peptide bonds forming long chained molecules, or polypeptides.

Analyses from the X-ray chromatography of DNA allowed researchers to conclude what three things?

Analyses of the scatterplots from this technique allowed them to measure the distance between atoms in DNA and they were able to conclude three things: 1) DNA has a consistent width, 2) within DNA is a repeating pattern and 3) the molecule must be helical.

Describe two ways that deoxyribonucleotides and ribonucleotides differ.

DNA deoxyribonucleotides versus RNA ribonucleotides. In ribonucleotides, the sugar component is ribose while in deoxyribonucleotides, the sugar component is deoxyribose. Instead of a hydroxyl group at the second carbon in the ribose ring, it is replaced by a hydrogen atom. Secondly, DNA house the nitrogenous base thymine, whereas RNA house uracil.

What synthesizes RNA?

DNA synthesized mRNA in a process known as transcription.

How is deoxyribose different than ribose?

Deoxyribose and ribose differ in the presence or absense of an oxygen at the 2 prime carbon. Ribose has an oxygen, Deoxyribose does not. Hence, deoxy-ribose.

What are the three types of interactions that can determine the tertiary structure of a proteins ?

Hydrogen bonding between R groups. Hydrophobic/hydrophillic interations and ionic bonding between R groups.

Watson and Crick suggested that Chargaff's discoveries suggested what two aspects of the secondary structure of DNA?

James Watson and Francis Crick suggested Chargaff's evidence strongly supports base pairing in DNA, in which deoxyribonucleotides of adenine attach to thymine (A↔T) and guanine attaches to cytosine (G↔C). In addition, Watson and Crick hypothesized that base pairing of deoxyribonucleotides suggested that DNA was most likely double stranded.

How do R-groups vary by polarity ?

Non-polar molecules have relatively equal distribution of electrons via covalent bonding, while polar molecules have an unequal distribution of electrons. The unequal distribution of electrons in polar molecules creates partially charged atoms (δ+, δ-).

Nucleotides are connected to each other by what type of bond?

Nucleotides (ribonucleotides and deoxyribonucleotides are connected by phosphodiester bonds, a covalent bond connecting the phosphorous of one nucleotide to the 3 prime carbon of an adjacent nucleotide.

Which components of the nucleotide compose the nucleic backbone?

Nucleotides (ribonucleotides and deoxyribonucleotides are connected by phosphodiester bonds, a covalent bond connecting the phosphorous of one nucleotide to the 3 prime carbon of an adjacent nucleotide.

How many amino acids exist in living organisms?

Of the more than 500 amino acids known, only 20 appear in proteins of living organisms.

Structurally, how are purines and pyrimidines different?

Purines and pyrimidines are nitrogenous bases that make up the two different kinds of nucleotide bases in DNA and RNA. The two-carbon nitrogen ring bases, adenine and guanine, are purines, while the one-carbon nitrogen ring bases, thymine, uracil and cytosine, are pyrimidines.

What is the overall structure of a proteins known as?

Quartenary structure.

Which of the four components of an amino acid differ from one to the next ?

R groups vary between amino acids.

RNA is composed of which nucleotides ?

Ribonucleeotides compose RNA.

How is sickled cell anemia a condition determined by the primary structure of hemoglobin?

Sickled cell anemia is caused by a single different amino acid in one protein, an alteration of the proteins primary structure.

What is the central dogma of molecular biology?

The central dogma of molecular biology describes the two-step process, transcription and translation, by which the information in genes flows into proteins: DNA → RNA → protein. Transcription is the synthesis of an RNA copy of a segment of DNA.

Who proposed the central dogma of molecular biology?

The central dogma of molecular biology is a phrase by Francis Crick, who proposed the double helix structure of DNA. It means that information passes from DNA to proteins via RNA, but proteins cannot pass the information back to DNA.

Deoxyribonucleotides have which four nitrogenous bases? RNA?

The nitrogenous bases for DNA are adenine, guanine, cytosine and thymine. RNA houses adenine, guanine, cytosine and uracil.

What two types of shapes are created by a protein's secondary structure?

The protein's secondary structure form either corkscrew-shaped structures, known as α-helices, or folded ribbon-shaped structures, known as β-pleated sheets.

What does base pairing refer to with regards to DNA?

The rules of base pairing (or nucleotide pairing) are: A with T: the purine adenine (A) always pairs with the pyrimidine thymine (T) C with G: the pyrimidine cytosine (C) always pairs with the purine guanine (G).

What are the pyrimidines and purines of DNA?

The two-carbon nitrogen ring bases, adenine and guanine, are purines, while the one-carbon nitrogen ring bases, thymine, uracil and cytosine, are pyrimidines.

How does uracil differ from thymine?

Thymine contains a methyl (CH3) group at number-5 carbon, whereas uracil contains hydrogen (H) molecule at number-5 carbon.

What technique did Franklin and Wilkins use to acquired evidence of DNA's molecular shape?

To acquire evidence of the actual molecular shape of DNA, Rosalind Franklin and Maurice Wilkins bombarded DNA with x-rays and analyzed how the radiation scattered, a technique known as x-ray chromatography.

What is the direct synthesis of mRNA known as?

Transcription is the first step of gene expression, in which a particular segment of DNA is copied into RNA (especially mRNA) by the enzyme RNA polymerase. Both DNA and RNA are nucleic acids, which use base pairs of nucleotides as a complementary language.

What does antiparallel refer to with regards to DNA?

Watson and Crick suggested that DNA is composed of two strands: one running 5' to 3' connected to a second strand running 3'to 5'. This orientation is called antiparallel.

What is the function of mRNA?

mRNA is synthesized by a specific sequence of DNA, known as a gene. mRNA serves as a template for the production of a protein.

Which biological molecule is capable of self replication?

DNA

What does DNA directly code for?

DNA directly codes for RNA: mRNA, tRNA and rRNA. DNA also codes for itself via replication.

What does DNA indirectly code for?

DNA indirectly codes for polypeptides and proteins via an intermediary called messenger RNA or mRNA.

What is the predominant role of RNA in the cell?

RNA predominately assists with the production of proteins in the cell. DNA transcribes mRNA. mRNA is read at a ribosome, which is composed of rRNA and protein, by tRNA. All of these RNAs work in conjunction to produce a protein.

Which carbon does phosphate bind to in a nucleotide?

The 3 prime carbon connects of one nucleotide connects to a phosphate group of an adjacent nucleotide binding them together in a phosphodiester bond.

What is the process of protein synthesis called?

Translation

Where is mRNA "read"?

mRNA is read at the ribosome and translated into a protein in a process known as translation.

What is the function of tRNA?

tRNA reads the mRNA at a ribosome synthesizing a protein.

What is the segment of DNA that codes for mRNA?

A gene is a segment of DNA that codes for a specific sequence of mRNA that is translated to produce a protein.

A nucleotide is composed of what three components?

A nucleotides is composed of a phosphate, a sugar and a nitrogenous based. Deoxyribonucleotides have the sugar deoxyribose, while ribonucleotides have ribose. The nitrogenous bases for DNA are adenine, guanine, cytosine and thymine. RNA houses adenine, guanine, cytosine and uracil.

What are the four nitrogenous bases of ribonucleotide?

Adenine, cytosine, guanine and uracil.

What did Chargaff discover in the 1950s that helped Watson and Crick unravel the secondary structure of DNA?

Chargaff discovered: 1. the relative abundance of guanine equals cytosine, and 2. the relative abundance of adenine equals thymine.

Why did Watson and Crick suggest that purines connect with pyrimidines between DNA strands?

For the width of DNA to be consistent with the variety of shapes found in nitrogenous bases, purines must connect with pyrimidines. A purine-purine base pairing creates a larger molecular width than observed, and a pyrimidine-pyrimidine base pairing would be too small.

What type of bond connects amino acids together?

Proteins are polymers of amino acids chained together by covalent bonds, known as peptide bonds.

Draw an amino acid. What are the adenine binds with thymine and guanine binds with cytosine between two DNA strands?

Investigating the shapes and interactions of these four nitrogenous bases, they discovered that guanine and cytosine were geometrically complements of each other and held together by three hydrogen bonds, while adenine and thymine are held together by two hydrogen bonds. Essentially, the A-T and C-G pairing are more stable than any other combination due to the complementarity of the molecular shape and hydrogen bond orientation.

Why did Watson and Crick suggest that adenine binds with thymine and guanine binds with cytosine between two DNA strands?

Investigating the shapes and interactions of these four nitrogenous bases, they discovered that guanine and cytosine were geometrically complements of each other and held together by three hydrogen bonds, while adenine and thymine are held together by two hydrogen bonds. Essentially, the A-T and C-G pairing are more stable than any other combination due to the complementarity of the molecular shape and hydrogen bond orientation.

A protein is composed of a chain of these monomers.

Proteins are polymers of amino acids.

Which type of R-groups bend toward water? Away from water? ?

Polar R-groups are hydrophilic, meaning they have an affinity for water due to hydrogen bonds between the partial charges of the R-group and the water molecules.Non-polar R-groups are repelled by water, or hydrophobic.

Where are proteins synthesized?

Proteins are synthesized at ribosomes within the cell.

What is the function of proteins in a cell?

Proteins are the internal machinery of a cell. Among the many different roles that proteins serve in the cell, proteins have structural roles to help the cell keep its shape, regulatory roles to control movement of particles in and out of the cell, and repair roles to help signal and and help with repair of a cell if it is damaged. Proteins are especially important in cell division because they control when it starts, ends, and every movement in between.

What are are ribosome made of?

Ribosomes are composed of ribosomal RNA and protein.

What type of chemical bonds determine a protein's secondary structure?

When amino acids are grouped into polypeptide chains, neighboring amino acids can interact via hydrogen bonding. These interactions can form a regular pattern, which increases the molecular stability of the polypeptide chain.

How does hydrogen bonding differ between alpha-helices and beta-pleated sheets?

Within a single amino acid of an α-helix polypeptide chain, the hydrogens of the amine groups face the opposite direction relative to the oxygens of the carboxyl groups. In a single amino acid of a β-pleated sheet, the oxygen of the carboxyl and the hydrogen of the amine group face in the same direction. In the adjacent amino acid, the oxygen and hydrogen both face in the opposite direction relative to the first. The third amino acid is in a similar orientation to the first, and so on.