Download WGU C785 BIOCHEMISTRY CERTIFICATION EVALUATION 2026 QUESTIONS WITH ANSWERS GRADED A+ and more Exams Biochemistry in PDF only on Docsity!
WGU C785 BIOCHEMISTRY CERTIFICATION
EVALUATION 2026 QUESTIONS WITH
ANSWERS GRADED A+
โโ Polymer. Answer: A long molecule consisting of many similar or identical monomers linked together. ex nucleic acids (dna rna) โโ Nucleotides KEY CONCEPTS. Answer: - Nucleic acids are polymers of nucleotides. A nucleotide consists of a nitrogenous base, a pentose sugar, and one or more phosphate groups.
- DNA contains adenine, guanine, cytosine, and thymine deoxyribonucleotides, whereas RNA contains adenine, guanine, cytosine, and uracil ribonucleotides.
- DNA is double-stranded and forms a double helix structure that allows for information storage. Prior to dividing , a cell copies all of its DNA using - DNA replication to ensure all new cells have the DNA they need.
- DNA Replication involves the formation of a replication fork, addition of RNA primers to create a "handle" for DNA polymerase, synthesis of the new DNA strand by DNA polymerase, and sealing the DNA backbone by DNA ligase.
- RNA is single-stranded and is grouped into three types of RNA: messenger RNA (mRNA), ribosomal RNA (rRNA), and transfer RNA (tRNA). All three types of RNA play an important role in the central dogma. โโ two types of nucleic acids. Answer: deoxyribonucleic acid (DNA) and ribonucleic acid (RNA) โโ DNA and RNA are. Answer: nucleic acids and polymers, which means they are made up of many smaller units (monomers) connected together, much like a string of pearls. The monomers of nucleic acids are known as nucleotides. Each nucleotide includes a nitrogen-containing base, a five-carbon sugar or pentose (pente means "five" in Greek), and one or more phosphates. โโ The monomers of nucleic acids(DNA and RNA) are known as. Answer: nucleotides = cytosine, guanine, thymine, adenine (DNA)
โโ DNA replication. Answer: is semi conservated โโ DNA replication steps. Answer: - First, the DNA must be separated. This creates a replication "fork" where the two original strands separate.
- Next, the new DNA is synthesized by a protein known as DNA polymerase (its name comes from its function - it makes a polymer of DNA nucleotides).
- DNA polymerase takes individual nucleotides and matches them up to the parental sequence to ensure they are a correct pair. If the pairing is correct, DNA polymerase bonds the nucleotide to the growing strand of DNA.
- uses RNA primers. The addition of a primer to the single-stranded DNA creates a double-stranded nucleic acid "handle" to which DNA polymerase can attach and start making DNA
- RNA primers (to allow DNA polymerase to bind), new strand synthesis by DNA polymerase, RNA primer removal by RNAase H, and sealing of the backbone "nicks" by DNA ligase.
โโ DNA polymerase has one problem - it can't start a new DNA strand because it only binds to double-stranded nucleic acids. How does the cell get around this?. Answer: uses RNA primers. The addition of a primer to the single- stranded DNA creates a double-stranded nucleic acid "handle" to which DNA polymerase can attach and start making DNA โโ DNA polymerase. Answer: has proofreading activity โโ Transcription. Answer: ~ synthesis of an RNA molecule from a DNA template ~ Takes place in the nucleus โโ Transcription. Answer: When information in a particular section of DNA is needed, the cell makes an RNA copy of that DNA section and that carries the information out of the nucleus to the rest of the cell. โโ Promoter. Answer: The initiation of RNA synthesis requires a specific DNA sequence at a site known as a promoter. The promoter is located just upstream of a gene and is the binding site for transcription factors that recruit the RNA polymerase
- splicing takes place
- Once the RNA is finished being made, the newly synthesized RNA is released as a single-stranded molecule. โโ coding DNA strand (non template) is the same as _______. Answer: mRNA strand โโ Non-coding (template) strand. Answer: 3'------>5' โโ RNA Polymerase. Answer: - The primary enzyme involved in transcription that reads the DNA sequence of a gene and produces a complementary mRNA molecule
- RNA polymerase separates the two DNA strands in a small portion of the DNA molecule to form a transcription bubble, thus allowing it to access the template strand and begin RNA synthesis. โโ Polyadenylated (Poly-A) Tail. Answer: a polyadenylated (poly-A) "tail" at the 3' end. The 5' cap is added to the 5' end of the nascent RNA during transcription, but the
poly-A tail is added to the 3' end of the RNA only after transcription termination. The capping and poly-A tail serve to protect the mRNA from degradation once it leaves the nucleus, as well as identify it as a mature mRNA ready to be translated. โโ Splicing. Answer: - The process in which portions of an mRNA sequence called introns (intervening sequences) are removed, and the remaining portions of the gene (expressed sequences, or exons) are joined together.
- Once splicing is complete, the mature, fully-processed RNA is ready for translation. โโ Exons. Answer: The expressed sequences from a new mRNA strand that REMAIN in the mRNA after splicing. The exons will be the part of the mRNA translated into protein โโ Introns. Answer: Intervening sequences in a newly made mRNA molecule that are REMOVED by splicing before the mRNA is released into the cytoplasm for protein synthesis (occurs during translation) โโ Translation.
Answer: the process of turning genes on and off and to change the way the gene is used โโ What three ways are genes regulated/expression?. Answer: 1. Transcription Factors - when a gene is turned off, the cell does not have transcription factors to bind to the promoter region. Polymerase will not recognize that promoter and transcribe that gene
- Alternative Splicing
- Epigenetics - DNA is wound around histones. If packed tightly, transcription is impeded and RNA polymerase cannot access the DNA. If it is wound loosely transcription is possible. โโ Codon. Answer: During translation the tRNA "decodes" the mRNA three bases at a time. These three bases located on mRNA are called a codon. โโ Transcription Factors. Answer: Specific proteins that recognize and bind to the promoter sequence of a gene. The binding of transcription factors helps to recruit RNA polymerase to the transcription start site to begin gene expression โโ Anticodon. Answer: The three bases of the mRNA codon are complementary (i.e., they base-pair) to three bases on the tRNA known as the anticodon
โโ Translation. Answer: The synthesis, or production, of protein by the ribosome using the sequence of messenger RNA (mRNA) as a template. โโ tRNA. Answer: The transfer RNA, or tRNA, are specialized molecules used by the ribosome to translate the mRNA sequence into protein. The tRNAs have an anticodon sequence that matches up to a specific codon on the mRNA. The codons correspond to a specific amino acid, which the tRNA brings to the ribosome for addition to the growing peptide chain. โโ elongation phase of translation. Answer: 1) Codon recognition: anticodon pairs with codon in A site
- Peptide bond formation: Polypeptide separates from P site and attaches to amino acid in A site
- Translocation: Ribosome translocates the tRNA with the polypeptide into the P spot โโ How are DNA and RNA different? How are DNA and RNA similar?. Answer: Both DNA and RNA contain adenine (A), guanine (G) and cytosine (C).
4.Double-stranded breaks
- non-homologous end joining, homologous recombination repair โโ Silent Mutations. Answer: point mutations that result in no change in amino acid sequence โโ missense mutation. Answer: point mutations that change a single base pair in a codon such that the codon now encodes a different amino acid โโ Nonsense mutation. Answer: point mutations that change a single base pair in a codon to a stop codon that terminates translation โโ frameshift mutation. Answer: Insertions or deletions of one or more base pairs (if the number of base pairs is not a multiple of 3) that disrupt the coding of a protein
- nucleotide excision repair used to repair this type of mutation โโ Sources of DNA damage.
Answer: 1. UV radiation - bases fuse together to form a thymine dimer that blocks DNA replication and transcription
- Ionizing radiation - strands break as well as create reactive O2 species that damage the bases
- chemicals - alter the structure of DNA bases
- Reactive O2 species - damage DNA bases โโ Nucleotide Excision Repair (NER). Answer: DNA damage repair mechanism where several nucleotides, usually around 30, are removed and replaced. Useful for deletions, insertions and heliz distortine lesions such as thymine dimers. (frameshift mutation) โโ Base Excision Repair (BER). Answer: DNA damage repair mechanism where a single nucleotide is replaced,
- DNA repair enzymes recognize and remove the damaged base
- DNA pol adds a new nucleotide
- ligase seals the remaining nick
repair follows the same steps as nucelotide excision repair. However, the base or bases that are removed during mismatch repair come from the newly synthesized strand rather than repair of parental DNA. โโ homologous recombination. Answer: Following a break in the two strands of DNA, the sequence is repaired by inserting a section of DNA that is identified as homologous. This can also occur without DNA damage to shuffle genes.
- used in double break demand โโ In the organization of DNA into chromosomes, DNA is wrapped around _________ to form nucleosomes. Nucleosomes are organized further to form a _____________.. Answer: In the organization of DNA into chromosomes, DNA is wrapped around histones to form nucleosomes. Nucleosomes are organized further to form a chromatin fiber. โโ Inheritance KEY CONCEPTS. Answer: Genes are located on chromosomes and come in pairs in most human cells. Each member of a gene pair (each copy of the gene) is known as an allele.
Genes are passed on from one generation to the other. The genotype (pair of genes) decide the phenotype (observable characteristics) of an individual. Inheritance is the passage of hereditary traits from one generation to the next. It is the process by which you acquired your characteristics from your biological parents and may transmit some of your traits to your children. Common inheritance patterns include: complete dominance, incomplete dominance, codominance, and sex-linked (X-linked) traits. โโ How many chromosome pairs does a human have?. Answer: 23 pairs (46 total chromosomes) โโ Genome. Answer: The whole set of genes that a person has โโ Phenotype. Answer: observable characteristics or traits that arise from genotype, some are not easy seen like...... ex blood type, color blindeness
โโ Recessive allele. Answer: The allele, whose presence is completely masked by a dominant allele, producing a recessive trait. ex b recessive trait โโ incomplete dominance. Answer: Produces different phenotypes based on the combination of alleles present in the heterzygotes. ex hair (wavy) โโ Codominance. Answer: Occurs when the effects of both alleles appear in the heterozygote (one allele is not dominated by the other) ex. blood type โโ sex-linked traits. Answer: result from sex-linked inheritance where the recessive trait predominantly impacts males and a dominant trait can impact both males and females
โโ Epigenetics. Answer: Study of how environmental and lifestyle factors can impact gene expression; above the genome โโ Epigenetics and the Environment. Answer: Researchers are studying how chromatin changes occur as a result of environmental factors such as diet and smoking. These changes occur via chemical modifications to both the DNA and the histone proteins that do not change the DNA sequence but do initiate epigenetic changes in chromatin structure that determine cellular phenotype. In other words, environmental stimuli can influence gene expression by altering how the DNA is packaged as chromatin. โโ sickle cell anemia. Answer: autosomal recessive trait disorder
- to have sickle cell anemia, you have to be born with the aa gene โโ hemophilia. Answer: An X-linked recessive disorder in which blood fails to clot properly, leading to excessive bleeding if injured. โโ Huntington's disease.
