Unit 6 AP Biology Exam Review

What are histones? What is the role of histones in regulating gene expression?

DNA wraps around Histone proteins in the nucleus. Sometimes DNA is wrapped so tightly that transcription can not happen.

Genotype is: Phenotype is:

The whole hereditary information of an organism is known as its genotype. The observed qualities of an organism, such as shape, development, or behavior, are referred to as phenotypes.

Regulatory sequences of DNA do not code for a protein. What is their purpose?

Turn on and off certain genes or proteins being made

To the right is a gel plate for an Electrophoresis machine. You have a sample of DNA that you want to run through the gel.

just read

Around 90% of the processed food sold in the United States contains Genetically Modified ingredients. Name two types of plants that have been genetically modified, what new trait they now have, and why it was developed (what is the benefit).

1. corn - larger, sweeter, juicer kernels with more bright yellow color = more food 2. apples - larger, firmer, less prone to bruising, sweeter, thicker skin - more food and more appealing to consumers

Percent of offspring that do not have Sickle Cell and are not susceptible to malaria _______

1/2

Percent of offspring have Sickle Cell disease _________ Percent of offspring susceptible to malaria _________

1: 4 1: 4

Now re-write the mRNA sequence with one point mutation that would be neutral to the organism with this sequence (recognize this point mutation is a reflection of a point mutation that would be in the DNA, transcribed here into mRNA). Translate your mutated sequence. Why is this mutation neutral?

A - U - G - G - A - A - C - A - G - G - U - ((C)) - A - G - A yep = start, glu, gin, val, arg

Now re-write the mRNA sequence with a point mutation that COULD be positive to the organism with this sequence. Translate the mutated sequence into amino acids. Why might this be a positive mutation?

A - U - G - G - A - A - C - A - G - G - U - A - ((A)) - G - A yep = start, glu, gin, stop

Re-write the mRNA sequence with one point mutation that would still lead to the same amino acid sequence. Put a line between the codons. Underline your point mutation.

A - U - G // - G - A - A //- C - A - G -// G - U - A -// A - G - ((G)) start, Glu, Gin, Val, arg

Draw a line between each codon. Then use the Codon Chart on the next page to translate this mRNA sequence into amino acids. A - U - G - G - A - A - C - A - G - G - U - A - A - G - A

A - U - G // - G - A - A //- C - A - G -// G - U - A -// A - G - A start, Glu, Gin, Val, arg

Come up with some way to remember (to link the facts together) that A and G are Purines and have a double ring, while C, T, and U are Pyrimidines and have just one ring. Then share your idea with someone and see what idea they came up with!

A and G got married and have 2 rings C, T, and U are fighters in 1 ring

Draw a simple diagram showing each way prokaryotes increase genetic variety. Then come up with a way to remember each one - somehow link the word with the process!

A bacterium takes up a fragment of DNA floating in its surroundings during transformation. A virus unintentionally moves DNA from one bacterium to another during transduction. DNA is transmitted between bacteria via a tube between cells in conjugation.

You will first cut the DNA sample into small pieces. What tool will you use to do this? (type of enzyme)

A restriction enzyme.

In your own words, what does it mean that DNA replication is a 'semiconservative' process?

An original DNA strand, which served as the template for the synthesis of the new strand, is one of the two strands of double-stranded DNA. DNA replication is a semiconservative process since one of the two strands is always conserved.

Explain why transcription and translation can happen at the same time in Prokaryotes, but not in Eukaryotic cells.

Because Prokaryotes lack a nucleus, transcription and translation can occur simultaneously. Ribosomes for translation can hook up with a developing mRNA as it is produced by RNA Polymerase.

You can get the polio vaccine one time and be immune for life, but you must take a flu vaccine each year to be immune for just that season. This is because the flu (and HIV as well) are retroviruses. How are retroviruses different from other viruses? How does this difference lead to the need to get a flu shot every year?

Because retroviruses are a type of virus, they have unique properties not found in other viruses. • Viruses include genetic material in the form of DNA or RNA, whereas retroviruses only contain RNA. Every year, you'll need a fresh flu shot since the virus's genetic code can mutate, rendering the prior vaccination ineffective.

Explain: What causes the DNA molecules to move through the gel? How does the gel separate the pieces by size?

DNA is a molecule with a negative charge. An electric charge flows through the gel when the Gel Electrophoresis machine is turned on, with a negative charge at the top and a positive charge at the bottom. The like charge near the top repels DNA, while the opposing charge towards the bottom attracts it. Smaller chunks pass through the gel more easily and get further down the gel.

What leads to cell differentiation during development? Use the word transcription factors in your answer.

Different transcription factors are expressed in different cell types, and these transcription factors turn on or off specific genes that lead to cell differentiation. Some genes, such as the HOX genes, act as master switches that govern fundamental aspects of the body plan and turn on in a predictable order during development.

You have roughly 20,000 genes in your genome - but the ability to produce over 2 million different proteins! How is this possible? (HINT read standard IST-1N6d)

Distinct parts of mRNA can be deleted to produce different RNA sequences and, as a result, proteins. Alternative splicing is used by the immune system to synthesize different-shaped protein antibodies from a single string of DNA code.

What is the 'Central Dogma' of Biology? ______ >> ________ >> _____________

Dna ---> RNA --> protien

TOPIC 6.6 Gene Expression and Cell Specialization

ENDURING UNDERSTANDING IST-2 Differences in the expression of genes account for some of the phenotypic differences between organisms. LEARNING OBJECTIVE IST-2.C Explain how the binding of transcription factors to promoter regions affects gene expression and/or the phenotype of the organism. ESSENTIAL KNOWLEDGE IST-2.C.1 Promoters are DNA sequences upstream of the transcription start site where RNA polymerase and transcription factors bind to initiate transcription. IST-2.C.2 Negative regulatory molecules inhibit gene expression by binding to DNA and blocking transcription. LEARNING OBJECTIVE IST-2.D Explain the connection between the regulation of gene expression and phenotypic differences in cells and organisms. ESSENTIAL KNOWLEDGE IST-2.D.1 Gene regulation results in differential gene expression and influences cell products and function. IST-2.D.2 Certain small RNA molecules have roles in regulating gene expression

TOPIC 6.7 Mutations

ENDURING UNDERSTANDING IST-2 Differences in the expression of genes account for some of the phenotypic differences between organisms. LEARNING OBJECTIVE IST-2.E Describe the various types of mutation. ESSENTIAL KNOWLEDGE IST-2.E.1 Changes in genotype can result in changes in phenotype— a. The function and amount of gene products determine the phenotype of organisms. The normal function of the genes and gene products collectively comprises the normal function of organisms. Disruptions in genes and gene products cause new phenotypes. IST-2.E.2 Alterations in a DNA sequence can lead to changes in the type or amount of the protein produced and the consequent phenotype. DNA mutations can be positive, negative, or neutral based on the effect or the lack of effect they have on the resulting nucleic acid or protein and the phenotypes that are conferred by the protein ILLUSTRATIVE EXAMPLES § Mutations in the CFTR gene disrupt ion transport and result in cystic fibrosis. § Mutations in the MC1R gene give adaptive melanism in pocket mice. ENDURING UNDERSTANDING IST-4 The processing of genetic information is imperfect and is a source of genetic variation LEARNING OBJECTIVE IST-4.A Explain how changes in genotype may result in changes in phenotype. ESSENTIAL KNOWLEDGE IST-4.A.1 Errors in DNA replication or DNA repair mechanisms, and external factors, including radiation and reactive chemicals, can cause random mutations in the DNA— a. Whether a mutation is detrimental, beneficial, or neutral depends on the environmental context. b. Mutations are the primary source of genetic variation. IST-4.A.2 Errors in mitosis or meiosis can result in changes in phenotype— a. Changes in chromosome number often result in new phenotypes, including sterility caused by triploidy, and increased vigor of other polyploids. b. Changes in chromosome number often result in human disorders with developmental limitations, including Down syndrome/ Trisomy 21 and Turner syndrome. ILLUSTRATIVE EXAMPLES § Antibiotic resistance mutations § Pesticide resistance mutations § Sickle cell disorder and heterozygote advantage LEARNING OBJECTIVE IST-4.B Explain how alterations in DNA sequences contribute to variation that can be subject to natural selection. ESSENTIAL KNOWLEDGE IST-4.B.1 Changes in genotype may affect phenotypes that are subject to natural selection. Genetic changes that enhance survival and reproduction can be selected for by environmental conditions— a. The horizontal acquisitions of genetic information primarily in prokaryotes via transformation (uptake of naked DNA), transduction (viral transmission of genetic information), conjugation (cell-to-cell transfer of DNA) and transposition (movement of DNA segments within and between DNA molecules) increase variation. b. Related viruses can combine/recombine genetic information if they infect the same host cell. c. Reproduction processes that increase genetic variation are evolutionarily conserved and are shared by various organisms.

TOPIC 6.5 Regulation of Gene Expression

ENDURING UNDERSTANDING: Differences in the expression of genes account for some of the phenotypic differences between organisms. LEARNING OBJECTIVE IST-2.A Describe the types of interactions that regulate gene expression. ESSENTIAL KNOWLEDGE IST-2.A.1 Regulatory sequences are stretches of DNA that interact with regulatory proteins to control transcription. IST-2.A.2 Epigenetic changes can affect gene expression through reversible modifications of DNA or histones. IST-2.A.3 The phenotype of a cell or organism is determined by the combination of genes that are expressed and the levels at which they are expressed— a. Observable cell differentiation results from the expression of genes for tissue specific proteins. b. Induction of transcription factors during development results in sequential gene expression LEARNING OBJECTIVE IST-2.B Explain how the location of regulatory sequences relates to their function. ESSENTIAL KNOWLEDGE IST-2.B.1 Both prokaryotes and eukaryotes have groups of genes that are coordinately regulated— a. In prokaryotes, groups of genes called operons are transcribed in a single mRNA molecule. The lac operon is an example of an inducible system b. In eukaryotes, groups of genes may be influenced by the same transcription factors to coordinately regulate expression.

TOPIC 6.2 Replication

ENDURING UNDERSTANDING: Heritable information provides for continuity of life LEARNING OBJECTIVE IST-1.M Describe the mechanisms by which genetic information is copied for transmission between generations. ESSENTIAL KNOWLEDGE IST-1.M.1 DNA replication ensures continuity of hereditary information— a. DNA is synthesized in the 5' to 3' direction. b. Replication is a semiconservative process—that is, one strand of DNA serves as the template for a new strand of complementary DNA. c. Helicase unwinds the DNA strands. d. Topoisomerase relaxes supercoiling in front of the replication fork. e. DNA polymerase requires RNA primers to initiate DNA synthesis. f. DNA polymerase synthesizes new strands of DNA continuously on the leading strand and discontinuously on the lagging strand. g. Ligase joins the fragments on the lagging strand. X The names of the steps and particular enzymes involved - beyond DNA polymerase, ligase, RNA polymerase, helicase, and topoisomerase - are beyond the scope of the AP Exam

TOPIC 6.8 Biotechnology

ENDURING UNDERSTANDING: Heritable information provides for continuity of life LEARNING OBJECTIVE IST-1.P Explain the use of genetic engineering techniques in analyzing or manipulating DNA. ESSENTIAL KNOWLEDGE IST-1.P.1 Genetic engineering techniques can be used to analyze and manipulate DNA and RNA— a. Electrophoresis separates molecules according to size and charge. b. During polymerase chain reaction (PCR), DNA fragments are amplified c. Bacterial transformation introduces DNA into bacterial cells. d. DNA sequencing determines the order of nucleotides in a DNA molecule. X The details of these processes are beyond the scope of this course. The focus should be on the conceptual understanding of the application of these techniques ILLUSTRATIVE EXAMPLES § Amplified DNA fragments can be used to identify organisms and perform phylogenetic analyses. § Analysis of DNA can be used for forensic identification. § Genetically modified organisms include transgenic animals. § Gene cloning allows propagation of DNA fragments

TOPIC 6.1 DNA and RNA Structure

ENDURING UNDERSTANDING: Heritable information provides for continuity of life. LEARNING OBJECTIVE IST-1.K Describe the structures involved in passing hereditary information from one generation to the next. ESSENTIAL KNOWLEDGE IST-1.K.1 DNA, and in some cases RNA, is the primary source of heritable information. IST-1.K.2 Genetic information is transmitted from one generation to the next through DNA or RNA— a. Genetic information is stored in and passed to subsequent generations through DNA molecules and, in some cases, RNA molecules. b. Prokaryotic organisms typically have circular chromosomes, while eukaryotic organisms typically have multiple linear chromosomes. IST-1.K.3 Prokaryotes and eukaryotes can contain plasmids, which are small extra-chromosomal, double-stranded, circular DNA molecules. LEARNING OBJECTIVE IST-1.L Describe the characteristics of DNA that allow it to be used as the hereditary material. ESSENTIAL KNOWLEDGE IST-1.L.1 DNA, and sometimes RNA, exhibits specific nucleotide base pairing that is conserved through evolution: adenine pairs with thymine or uracil (A-T or A-U) and cytosine pairs with guanine (C-G)— a. Purines (G and A) have a double ring structure. b. Pyrimidines (C, T, and U) have a single ring structure.

TOPIC 6.3 Transcription and RNA Processing

ENDURING UNDERSTANDING: Heritable information provides for continuity of life. LEARNING OBJECTIVE IST-1.N Describe the mechanisms by which genetic information flows from DNA to RNA to protein. ESSENTIAL KNOWLEDGE IST-1.N.1 The sequence of the RNA bases, together with the structure of the RNA molecule, determines RNA function— a. mRNA molecules carry information from DNA to the ribosome. b. Distinct tRNA molecules bind specific amino acids and have anti-codon sequences that base pair with the mRNA. tRNA is recruited to the ribosome during translation to generate the primary peptide sequence based on the mRNA sequence. c. rRNA molecules are functional building blocks of ribosomes. IST-1.N.2 Genetic information flows from a sequence of nucleotides in DNA to a sequence of bases in an mRNA molecule to a sequence of amino acids in a protein. IST-1.N.3 RNA polymerases use a single template strand of DNA to direct the inclusion of bases in the newly formed RNA molecule. This process is known as transcription. ST-1.N.4 The DNA strand acting as the template strand is also referred to as the noncoding strand, minus strand, or antisense strand. Selection of which DNA strand serves as the template strand depends on the gene being transcribed. IST-1.N.5 The enzyme RNA polymerase synthesizes mRNA molecules in the 5' to 3' direction by reading the template DNA strand in the 3' to 5' direction. IST-1.N.6 In eukaryotic cells the mRNA transcript undergoes a series of enzyme-regulated modifications— a. Addition of a poly-A tail. b. Addition of a GTP cap. c. Excision of introns and splicing and retention of exons. d. Excision of introns and splicing and retention of exons can generate different versions of the resulting mRNA molecule; this is known as alternative splicing.

TOPIC 6.4 Translation

ENDURING UNDERSTANDING: Heritable information provides for continuity of life. LEARNING OBJECTIVE IST-1.O Describe how the phenotype of an organism is determined by its genotype. ESSENTIAL KNOWLEDGE IST-1.O.1 Translation of the mRNA to generate a polypeptide occurs on ribosomes that are present in the cytoplasm of both prokaryotic and eukaryotic cells and on the rough endoplasmic reticulum of eukaryotic cells. IST-1.O.2 In prokaryotic organisms, translation of the mRNA molecule occurs while it is being transcribed. IST-1.O.3 Translation involves energy and many sequential steps, including initiation, elongation, and termination X The details and names of the enzymes and factors involved in each of these steps are beyond the scope of the AP Exam IST-1.O.4 The salient features of translation include— a. Translation is initiated when the rRNA in the ribosome interacts with the mRNA at the start codon. b. The sequence of nucleotides on the mRNA is read in triplets called codons. c. Each codon encodes a specific amino acid, which can be deduced by using a genetic code chart. Many amino acids are encoded by more than one codon. d. Nearly all living organisms use the same genetic code, which is evidence for the common ancestry of all living organisms. e. tRNA brings the correct amino acid to the correct place specified by the codon on the mRNA. f. The amino acid is transferred to the growing polypeptide chain. g. The process continues along the mRNA until a stop codon is reached. h. The process terminates by release of the newly synthesized polypeptide/protein. X Memorization of the genetic code is beyond the scope of the AP Exam IST-1.O.5 Genetic information in retroviruses is a special case and has an alternate flow of information: from RNA to DNA, made possible by reverse transcriptase, an enzyme that copies the viral RNA genome into DNA. This DNA integrates into the host genome and becomes transcribed and translated for the assembly of new viral progeny. X The names of the steps and particular enzymes involved—beyond DNA polymerase, ligase, RNA polymerase, helicase, and topoisomerase—are beyond the scope of the course and the AP Exam.

In general, most species on the planet have some way of increasing genetic variation, and all species are susceptible to random mutation. Why is genetic variation shared across all species? What is the advantage to genetic variation?

Environments do not stay the same indefinitely. When the environment changes, a positive attribute may become a disadvantage. Natural selection has more to work with when there is genetic diversity. If (when) the environment changes and there is no genetic diversity, a species will be unable to adapt and would most likely become extinct. However, if the population is diverse, there is a potential that certain variations will emerge.

There is a mutation in the regulatory gene that turns off Gene B, such that the regulatory protein does not bind to the DNA. What does this mean for the production of Protein B? Explain.

If the transcription factor is the wrong shape, it will not recognize he specific sequence on the DNA it is supposed to bind to. In this case, if the regulatory protein can not bind to the regulatory sequence, it will be permanently turned on, continually making protein B.

Briefly describe what happens in each stage of translation. Include the roles of rRNA, mRNA, tRNA, codons, anticodons, and amino acids. initiation elongation termination

Initiation is the first step. The Origin of Replication refers to the point at which replication begins. Helicase initiates the strand separation process, which results in the development of the replication fork. Elongation is the second step. The enzyme DNA Polymerase III creates the new strand by reading the template strand's nucleotides and adding one nucleotide after the other. If the template has an Adenine (A), it will only add a Thymine (T). Termination is the third step Polymerase III creates a gap or two between Okazaki fragments while adding nucleotides to the lagging strand and producing Okazaki fragments.

Explain or draw the steps showing how pharmaceutical companies can use bacterial transformation to make human proteins (like insulin).

Insulin is made by combining human and bacterial DNA. Human DNA is introduced into a bacteria's plasmid.

The sickle cell gene is a result of a single base pair mutation. It is a recessive trait that can lead to a shortened life-span for people who are homozygous- however in some areas of Africa there is a very high incidence of Sickle Cell disease. Why is this? Use the words natural selection and heterozygote advantage in your explanation.

It is very high in Africa because being heterozygous for sickle cell has the benefit of conferring malaria resistance. This indicates that it aided in the improvement of the individual's fitness, as measured by the allele frequency spread.

Define microRNA: What does microRNA do?

MicroRNA is a type of RNA that binds to mRNA and prevents it from being translated, which is another way to control gene expression.

What is the difference between a muscle cell and a nerve cell? Use the words Tissue Specific, Differentiation, Gene Expression, and Proteins in your answer.

Muscle cells and nerve cells have distinct gene expression patterns. In a muscle cell, tissue-specific genes are turned on (for example, actin and myosin), whereas gene expression in a nerve cell is different. The proteins that the cell produces cause it to become specialized, or differentiated, for its specific function in the body.

Draw a plasmid. Where are plasmids found in Prokaryotic cells? Where are they found in Eukaryotic cells (HINT consider the evolution of some Eukaryotic organelles!)?

Plasmids are small rings of DNA free floating inside Prokaryotes. They are also found in mitochondria and chloroplasts, consider the Endosymbiotic Theory that these organelles were once free-living prokaryotes.

Based on their structure (shape) explain why purines must always match with pyrimidines. In your explanation, include how a proofreading enzyme would identify a location where two purines are accidentally matched up, and a location where two pyrimidines are matched up.

Purines pair with pyrimidines because their size and shape make them a perfect fit for hydrogen bonding

What does each of these numbers represent in the diagram of the lac operon?

RNA polymerase Repressor Promoter Operator Inducer proteins

Why is it beneficial for single cellular organisms to be able to regulate their gene expression?

Single-celled organisms can only use the resources available to them in their surroundings. It's a waste of resources if it's producing proteins that aren't useful at the time. Lactase is only produced by bacteria when lactose sugar is present in the environment.

Okay, but why can't T (a pyrimidine) match with G (a purine)? Based on the number of hydrogen bonds that are available in adenine, thymine, guanine and cytosine, explain why A always matches with T, and C with G. In your explanation, include how a proofreading enzyme would identify a location where G and T are accidentally matched up, and a location where A and C are matched up.

The base pairing rule in DNA asserts that each base has a limited number of accessible bonds to allow complementary base pairing, and that each base can only bind with a single base partner. This is the best explanation for why adenine only links with thymine and guanine only bonds with cytosine. Nitrogenous bases that are hydrogen-bonded are known as base pairs. Cytosine can be broken down into three different forms.

Briefly explain in your own words how the base pairing rules of DNA lead to its ability to be used as the hereditary material of life (aka, to be copied and passed to a resulting daughter cell).

The base pairing rules for DNA are governed by the complementary base pairs: adenine (A) with thymine (T) in an A-T pairing and cytosine (C) with guanine (G) in a C-G pairing. Conversely, thymine only binds with adenine in a T-A pairing and guanine only binds with cytosine in a G-C pairing.

On diagram, label the leading strand and the lagging strand - briefly explain why Replication works a bit differently on the leading vs. lagging strand. Use the word antiparallel

The primary distinction between the leading and lagging strands is that the leading strand is the DNA strand that develops continuously during DNA replication, whereas the lagging strand is the DNA strand that grows in small segments known as Okazaki fragments. As a result, the leading strand does not require ligase to create a continuous strand, whereas the lagging strand must.

What would happen if there was a mutation in the regulatory gene for the lac operon so that the regulatory protein did not bind to the operator?

The regulatory protein is encoded by the regulatory gene (the repressor). If the Repressor did not attach to the operon, it would remain active and produce lac proteins even if lactose was not present.

Put a star beside the antisense strand. Why would this strand (that is used as a template for RNA Polymerase) be called the antisense, or noncoding strand? Explain.

The template strand, also known as the "Antisense strand," runs in the opposite direction of the coding strand, 3'- 5'. It has nucleotide sequences that are complementary to the transcribed mRNA. After transcription, the mRNA undergoes post-transcriptional changes before being transformed into mature mRNA. Anticodons, which carry triplet codes or triplet nucleotide sequences, are also found on the template strand.

The promoter region of Gene A has a mutation such that the necessary transcription factor does not bind to it. This transcription factor turns on the gene. What does this mean for the production of Protein A? Explain.

The transcription factor's form is tailored to bind to a certain DNA sequence. It will not identify the site and will not bind if the sequence is incorrect. In this situation, the gene will be permanently disabled, preventing the production of protein A.

How did Crick, Watson, Franklin and Wilkins contribute to our knowledge of DNA?

They revealed the double helix structure of the DNA molecule.

The lac operon is an INDUCIBLE operon. What does this mean? How does the operon turn on? (be specific to the lac operon).

This indicates that it is in the 'off' state by default, with the repressor tied to the operator. In the presence of an inducer - lactose - it can be INDUCED to turn on. When lactose is available, it binds to the repressor, causing it to alter form and fall off the operator, allowing RNA Polymerase to translate the operon's proteins.

What would happen if there was a mutation in the regulatory gene for the lac operon so that the regulatory protein did not bind to lactose sugar?

When lactose sugar binds to the promoter, the regulatory protein (the repressor) is released, enabling transcription to take place. If lactose could not attach to the protein, the operon would remain 'off' even if lactose was present, preventing the bacteria from producing the enzymes required to digest lactose.

In the box, draw a punnett square showing the resulting offspring of two heterozygous individuals for the sickle cell trait.

but 2 would be heterozygous one would be dominate and one would be ressive

Cell Specialization is the process of stem cells becoming...

compartmentalized

How can you remember that it is the exons that stay and the introns that must be removed during mRNA processing? Come up with a creative way to remember and share it with someone else.

exons are expressed introns are thrown out

Describe an environment where this mutation would be positive (beneficial).

in the artic or snowy environment where the rabbit would blend into its surroundings

A wild rabbit is born with a mutation that causes his fur to be white. Describe an environment where this mutation would be negative (detrimental).

in the forest where it would be more advantageous to blend into the dark colors of the forest floor

What does the word 'transgenic' literally mean (its word parts) ____________ _____________

movement race

Here is a normal sequence of mRNA. Use a Codon Chart to transcribe and translate it into its amino acid sequence (this is the same sequence in 6.4) A - U - G - G - A - A - C - A - G - G - U - A - A - G - A

start, glu, gin, val, arg

Describe an environment where this mutation would be neutral.

where it was a mixture of the 2 climates so it would be useful sometime but not always

A scientist has noted the gene expression of a group of cells. Read the unique gene that is expressed and determine what type of cell it must be. Achedocholine Hemoglobin Actin and myosin Antibodies Insulin

Achedocholine is a neurotransmitter that nerve cells release to communicate with other cells. Hemoglobin is an iron-containing protein molecule found in red blood cells and is responsible for transporting oxygen throughout the body. Actin and myosin are two proteins that help muscles produce contractile filaments. cellular Immunity is defined by antibodies, and protein is defined by globulin. Insulin is a hormone that is produced by the pancreas.

What is the significance of this famous experiment (what does it demonstrate)?

Alfred Hershey and Martha Chase conducted a series of studies in 1952 that helped to prove that DNA is genetic material. Despite the fact that biologists had known about DNA since 1869, many scientists still assumed that proteins contained the information for inheritance at the time because DNA looked to be an inactive molecule and was located in the nucleus.

A always matches with T, and G always matches with C.....but why? Proofreading enzymes run along the DNA molecule to be sure there are no mis-pairings between bases, but how do they know when a mistake has happened?

By matching nucleotide bases on messenger RNA with their complementary bases on transfer RNA, organisms may build double-stranded DNA from a single strand template, produce messenger RNA from DNA, and manufacture proteins from individual amino acids. During the synthesis of new DNA strands, DNA proofreading is necessary because if there is a mistake, the entire strand will be destroyed.

Why is it beneficial for cells of a multicellular organism to be able to regulate their gene expression?

Cells are differentiated to do a particular job.

What is the purpose of the poly-A tail and the GTP cap?

The Poly A Tail with the 5' Cap The enzyme guanylyl transferase adds the cap. The reaction between the 5' end of the RNA transcript and a guanine triphosphate (GTP) molecule is catalyzed by this enzyme. Once in situ, the cap aids in the identification of messenger RNA by ribosomes during protein translation.

In your own words, describe the job of each type of RNA, using the given word... mRNA use the word 'message' tRNA use the word 'transfer' rRNA use the word 'ribosome'

The genetic code from DNA is transcribed into a form that can be read and used to produce proteins by mRNA. mRNA transports genetic information from a cell's nucleus to its cytoplasm. rRNA is found in the cytoplasm of a cell, which also contains ribosomes. The translation of mRNA into proteins is directed by rRNA. tRNA is a type of RNA that is found in the cytoplasm of cells and is involved in protein synthesis. The benefits of RNA transfer

This is the lac operon of prokaryotic cells. What does it code for?

The proteins needed to breakdown the sugar lactose.

Do you think GMO foods should be labeled in the store? Why or why not?

Yes, since even if they've been tested and regulated, they should still state upfront that they're not organic and have undergone some chemical testing for those who wish to avoid it.

Then you must make many many copies of the DNA sample. What process will you use to do this?

You will use a Polymerase Chain Reaction machine, or PCR machine.

Name two reasons that a scientist might use an Electrophoresis machine.

dna analysis protien and antibody interactions