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- Biology Laboratory Manual B Laboratory Skills Answers Key
- Biology Laboratory Manual B Laboratory Skills Using Graphing Skills Answers
- Biology 1 Lab Manual Answers
- General Biology Laboratory Manual Answers
- Biology Laboratory Manual B Laboratory Skills Answers
Our genetic information is coded within the macromolecule known as deoxyribonucleic acid (DNA). DNA belongs to a class of organic molecules called nucleic acids. The building block, or monomer, of all nucleic acids is a structure called a nucleotide. A nucleotide has three parts: phosphate, deoxyribose sugar, and a nitrogen base.
There are four different nucleotides that make up a DNA molecule, each differing only in the type of nitrogenous base. These include adenine (A), thymine (T), cytosine (C), and guanine (G), often indicated by their first letters only.
James Watson and Francis Crick discovered the three dimensional shape of DNA in the early 1950s. The shape, which they described as a double helix, has the shape of a twisted ladder.
The Genetic Code
Think of the four nucleotides that make up DNA as the letters of an alphabet. To spell out a word (in this case an amino acid) three “letters” from our alphabet are required. Since only about 20 amino acids make up all the proteins, having a four-letter alphabet is more than sufficient to spell out the 20 “words” (see the calculations that follow). The genetic code is universal (almost) for all living things. What this means is that the triplet code spells the same amino acid in different organisms, from dolphins to plants to bacteria!
Sequence of Nucleotides | # Amino Acids Coded |
---|---|
one | 41 = 4 (not enough) |
two | 42 =16 (not enough) |
three | 43 =64 (more than enough) |
The Gene Concept
Think of a gene as a segment of DNA on a chromosome that codes for a series of amino acids that when linked together makes up what is known as a polypeptide. Polypeptides are then folded into complex three-dimensional shapes that become functional proteins.
The Central Dogma
All organisms use the same fundamental mechanism for gene expression.
DNA → RNA → Polypeptide → Protein
Biology Laboratory Manual B Laboratory Skills Answers Key
Protein Synthesis
Protein synthesis is a two step process.
DNA —(transcription)→ RNA —(translation)→ Polypeptide
Transcription happens when the information from the DNA template is transcribed onto another form of nucleic acid known as ribonucleic acid or RNA (actually messenger RNA).
Translation happens when the information from the language of nucleic acid is translated into the language of proteins.
Part 1: DNA to Protein Exercise
Biology Laboratory Manual B Laboratory Skills Using Graphing Skills Answers
The following DNA sequence is part of the gene that controls dimples. Decode the DNA message into mRNA, tRNA and finally amino acids. Use the genetic code chart to fill in the table below.
Note: The genetic code is based on mRNA (not DNA or tRNA). When you have finished this, you will be able to determine the phenotype of the person the DNA came from. (If arginine is the 3rd amino acid, the person will have dimples.)
DNA | mRNA codon | tRNA anticodon | Amino Acid |
---|---|---|---|
C G A | |||
G T C | |||
G C A | |||
T A A |
- Does the person with the sequence above have dimples?
- What two great tasks are carried out by our genetic machinery?
- What name do we call a three-nucleotide sequences of mRNA?
- How many DNA bases does it take to code for an RNA codon?
- How many amino acids does an RNA codon code for?
- What brings amino acids to the ribosome
- What is the difference between transcription and translation?
- True or false: Most of the DNA in the human genome codes for proteins.
Part 2: Protein Synthesis Exercise
DNA: 3′ AG C C G T A GAA T T 5′
- Using this strand of DNA as a template, draw a picture of the complete DNA molecule. Include all parts of the DNA molecule. You do not need to draw your molecule with atomic accuracy.
- Now draw a complete picture of the mRNA strand that will be made from this DNA. Label the 5′ and 3′ ends of your mRNA strand. (Use the given DNA strand at the top of this page as your template . . .)
- Carefully indicate the codons present in the mRNA strand from question 2.
- Draw a complete picture of all the tRNA molecules that will match up with the codons from the previous question. Include all appropriate amino acids in your picture, and do not mix up their order!
- Draw a picture of the completed protein coded for by this strand of DNA (abbreviations are fine). Show the amino acids in the same order they would be observed in the finished protein.
Part 3: Protein Synthesis Bingo
Fill in the boxes with 16 of the 20 amino acids. Every bingo square will be unique. Then listen as random nucleotide sequences are pulled from the hat. Listen carefully to what kind of sequence is called! Use the mRNA codon chart on the previous page to determine the amino acid associated with each sequence. (Printable version here.)
alanine—ala—A | cysteine—cys—C | histidine—his—H | methionine—met—M | threonine—thr—T |
arginine—arg—R | glutamine—gln—Q | isoleucine—ile—I | phenylalanine—phe—F | tryptophan—trp—W |
asparagine—asn—N | glutamic acid—glu—E | leucine—leu—L | proline—pro—P | tyrosine—tyr—Y |
aspartic acid—asp—D | glycine—gly—G | lysine—lys—K | serine—ser—S | valine—val—V |
Sequence Called | DNA? mRNA? tRNA? | Codon | AA |
1 | |||
2 | |||
3 | |||
4 | |||
5 | |||
6 | |||
7 | |||
8 | |||
9 | |||
10 | |||
11 | |||
12 | |||
13 | |||
14 | |||
15 | |||
16 | |||
17 | |||
18 |
Part 4: Wheat Germ Extraction
Wheat germ is the sprouting embryo contained within a wheat kernel (the wheat seed). The remainder of the wheat kernel is called the endosperm, and is the food storage site for the developing embryo. Our task today is to break down the cells within the wheat germ and remove the DNA.
Earn coins and tools to help you in your search. 8 themed destinations for all your searching pleasures. Roadfood, What all hidden object games should beThis game is great, it is pure hidden object searches, no storyline or mysteries or puzzles, just lots and lots of hidden object searches. Two styles of searching for items!. Games for mac hidden objects.
Materials
- Raw, untoasted wheat germ (2 g)
- Adolph’s natural meat tenderizer (unseasoned)
- Liquid dishwashing detergent (Palmolive) (3 mL)
- 1M sodium bicarbonate—NaHCO3 (5mL)
- Ice cold 95% ethanol (20mL)
- Tap water
- Water bath (55° C)
- 250 ml beaker
- Thermometer
- Graduated cylinder (10mL)
- Serological pipette, 10 mL
- Glass stirring rod
- Glass DNA hook
- Ice bath
Procedure
- Measure 45 mL of tap water into your beaker using the graduated cylinder, and place it in the warm water bath (55° C). Allow it a few minutes to warm up. Do not allow the temperature of the bath to exceed 60° C!
- Sprinkle in 2g of wheat germ into the beaker and gently stir in 3 mL of detergent. Incubate this mixture in the warm water bath for 5 minutes.
- Detergents dissolve lipids and proteins that form the cell membranes found in the wheat germ by disrupting the chemical bonds that hold the membrane together. This releases the cell’s contents, including the DNA held within the nucleus, into the solution.
- The warm water bath denatures enzymes that might otherwise damage the DNA, and it also helps the detergent work more effectively. If your water bath is too hot, then your DNA will become damaged.
- After 5 minutes, gently stir in 2 g of meat tenderizer and 5mL of the 1M sodium bicarbonate solution. Incubate this mixture at 55° C for an additional 15–20 minutes.
- Eventually, even at 55° C, the DNA would be damaged, so this additional incubation period must not exceed 15–20 minutes.
- The sodium bicarbonate acts as a buffer that maintains a near-neutral pH in the solution. This ensures the DNA remains stable, and it also enables the enzyme found in the meat tenderizer to be most effective.
- The meat tenderizer contains a proteolytic enzyme that degrades the proteins found in the nuclear membrane, ultimately freeing the DNA into solution.
- Transfer the beaker containing the wheat germ mixture to an ice bath for a few minutes to quickly cool it to room temperature. Gently stir during this time.
- The ice bath cools down the mixture so that the DNA is not damaged by the heat!
- Using the serological pipet, carefully layer 10 mL of ice-cold alcohol over the wheat germ solution in the beaker. Allow the alcohol to flow from the pipet with the pipet tip held against the inside surface of the beaker, just above liquid level. If the DNA does not appear, repeat this step.
- When the dissolved DNA makes contact with the very cold alcohol, the alcohol effectively dehydrates the DNA and it precipitates from the solution. This is because DNA is insoluble in the alcohol (and this is especially true of ice COLD alcohol).
- If carried out accurately, long strands of DNA will form at the interface between the alcohol and the original solution. These can be physically spooled using the glass DNA hook.
- Using the DNA hook, attempt to spool the DNA using a slow, twirling motion.
Color it for mac os x. Show your DNA to your instructor for credit!
Learning Objectives
Biology 1 Lab Manual Answers
- Recognize standard safety attire and procedures for performing biology experiments.
- Identify important safety considerations for common laboratory tools and chemicals.
- Explain how to locate and evaluate information about chemical substances using Materials Safety and Data Sheets (MSDS).
- Identify emergency response procedures in case of accident or injury while performing biology experiments.
- Identify common laboratory tools that measure temperature, volume, and mass.
- Describe proper usage and measurement techniques for common laboratory tools.
Lab 1 : Orientation
Even if you do not have your lab kit yet, you can still complete this lab. Get ready for biology lab with this orientation video.
Read Lab 1 in your lab manual, watch the videos, and complete all online activities before completing any graded assessments.
Estimated Completion Time for Lab: 1 hour
Allow additional time to complete your reporting activities after finishing lab.
General Biology Laboratory Manual Answers
Part 1: Safety
Both safety videos must be viewed and all safety assignments must be submitted before attempting any other lab activities in this course.
View this safety video to ensure you recognize the proper techniques to minimize risk when performing biology lab experiments at home.
In addition to the biology safety video above, you must also view the eScience safety video included on the CD packaged with the lab kit. This video is also available directly from the website for eScience Labs, Inc.
Part 2: Equipment and Measurement
Answer these questions after viewing the video about ‘Measuring Liquids Accurately’.
Biology Laboratory Manual B Laboratory Skills Answers
Practice selecting the proper equipment for accurate measurement of chemicals.
Graded Materials
- Lab Report
Click on the link below to open the 'Lab 1 Report' form. Complete the lab report form and save the completed PDF with your last name and lab number (for example: jones_lab1.pdf). Submit as directed by your instructor.
Lab 1 Report - Safety Quiz
To demonstrate successful completion of all safety materials, you must also take a graded quiz on laboratory safety. You can find the Safety Quiz in the Lab Quizzes section of the Test and Quizzes tab.