BIOL 112 Lecture Notes - Lecture 3: Homeostasis, Weak Base
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Part A
Which answer is a true statement about pH values?
Part A
Which answer is a true statement about pH values?
Which answer is a true statement about pH values?
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Part B
What conditions must be met in order for an aqueous solution to be called âneutralâ?
What conditions must be met in order for an aqueous solution to be called âneutralâ?
Pure water has a pH of 0. |
pH is important in life mainly because it affects the cohesion of water. |
A high pH corresponds to a high H+ concentration. |
Stomach juice has a high pH. |
None of the above. |
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Part C
Factory smoke has led to acid rain that lowered the pH of a lake to 5.0. What is the H+ concentration in the lake?
Factory smoke has led to acid rain that lowered the pH of a lake to 5.0. What is the H+ concentration in the lake?
The hydronium ion concentration is greater than the hydroxide ion concentration. |
The concentrations of hydronium and hydroxide ions are equal. |
There are no hydronium or hydroxide ions present in the solution. |
The hydroxide ion concentration is greater than the hydronium ion concentration. |
None of the above. |
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Incorrect; One attempt remaining; Try Again
No, there's a power-of-ten relationship between the pH and the concentration. Maybe you should review the lesson.
Part D
Your tank of swamp fish needs a pH of 5, and the pH is 7 at present. What should you do to the H+ concentration?
Your tank of swamp fish needs a pH of 5, and the pH is 7 at present. What should you do to the H+ concentration?
log (5) M |
105 M |
10-5 M |
5% |
5.0 M |
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Part E
In a washing machine, the detergent raised the pH to 9.0. The concentration of OH- in the solution is ...
In a washing machine, the detergent raised the pH to 9.0. The concentration of OH- in the solution is ...
Cut it in half. |
Double it. |
Reduce it to 1/100 of its present value. |
Raise it to 100 times its present value. |
Raise it to 200 times its present value. |
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Part F
Your tank of alkali fish needs a pH of 8, and the pH is 6 at present. What should you do to the H+ concentration?
Your tank of alkali fish needs a pH of 8, and the pH is 6 at present. What should you do to the H+ concentration?
Reduce it to 1/200 times its present value. |
Double it. |
Cut it in half. |
Reduce it to 1/100 of its present value. |
Raise it to 100 times its present value. |
10-5 M |
10-9 M |
10-1 M |
5 M |
Can't tell without more information. |
Part B
What conditions must be met in order for an aqueous solution to be called âneutralâ?
Pure water has a pH of 0. |
pH is important in life mainly because it affects the cohesion of water. |
A high pH corresponds to a high H+ concentration. |
Stomach juice has a high pH. |
None of the above. |
Part C
Factory smoke has led to acid rain that lowered the pH of a lake to 5.0. What is the H+ concentration in the lake?
The hydronium ion concentration is greater than the hydroxide ion concentration. |
The concentrations of hydronium and hydroxide ions are equal. |
There are no hydronium or hydroxide ions present in the solution. |
The hydroxide ion concentration is greater than the hydronium ion concentration. |
None of the above. |
Your tank of swamp fish needs a pH of 5, and the pH is 7 at present. What should you do to the H+ concentration?
log (5) M |
105 M |
10-5 M |
5% |
5.0 M |
Part E
In a washing machine, the detergent raised the pH to 9.0. The concentration of OH- in the solution is ...
In a washing machine, the detergent raised the pH to 9.0. The concentration of OH- in the solution is ...
Cut it in half. |
Double it. |
Reduce it to 1/100 of its present value. |
Raise it to 100 times its present value. |
Raise it to 200 times its present value. |
SubmitHintsMy AnswersGive UpReview Part
Part F
Your tank of alkali fish needs a pH of 8, and the pH is 6 at present. What should you do to the H+ concentration?
Reduce it to 1/200 times its present value. |
Double it. |
Cut it in half. |
Reduce it to 1/100 of its present value. |
Raise it to 100 times its present value. |
10-5 M |
10-9 M |
10-1 M |
5 M |
Can't tell without more information. |
Life Chemistry LabReport
- Elements of Living Organisms
- Name the five most abundant elements found in the humanbody.
- Cells organize into tissues which work together to form
- What is the difference between an atom and an element?
- Molecules
- Is glucose an atom or molecule? What are the atoms inglucose?
- How many bonds can oxygen form?
- Is C6H12O6 a molecular orstructural formula? What is the name of this molecule?
- Based on lab, Section II, draw and label a ball and stickrepresentation of a carbon dioxide, water and ethyl alcoholmolecule. Use circles to designate atoms and lines for bonds, thenindicate the chemical symbol for each atom. Sign, date and preparean image of your drawing and include it with this lab report.
- Molecular Make Up of Living Organisms
- Name the four groups of organic molecules.
- _______ are the most abundant organic molecules in livingorganisms.
- Name a polysaccharide, monosaccharide, protein and alipid.
- Go to the lab, Section 3, Exercises 2, 3, 4 and 5 to completethe following table:
Type of Organic Molecule | Reagent | Sample Tested | Positive Color | Negative Color |
Carbohydrate (starch) | Iodine | |||
Sugar | Benedictâs solution | |||
Lipid (fat) | Sudan IV | |||
Protein | Biuret |
- Go to the lab, Section 3, Exercise 6 to locate starch in potatocells. Describe the microscopic appearance of starch in terms ofcolor and location within the cells.
- Measurement of pH
- What substance has an equal number of hydrogen ions(H+) and hydroxide ions (OH-)?
- What is the pH of the above substance?
- How does the addition of hydroxide ions (OH-) affectthe pH of your stomach?
- Go to lab, Section 4, Exercise 7 to test the pH of commonsolutions. Which solution tested had a pH closest to neutral? Whichsolution was most acidic?
Summary Questions
- What is the smallest subunit of carbohydrates?
- Which reagent could be used to test for diabetes?
- A member of your family has a high blood cholesterol count. Yousee âfat freeâ crackers in the grocery store and decide to test theproduct for the presence of lipids. How would this testproceed?
- A family member has been cautioned about eating foods high insugar. Explain how a test could be run for the presence ofsugar.
- Explain how to test for the presence of protein in milk.
- A friend complains of stomach acidity. Which substance testedmight safely help relieve your friendâs symptoms?
- Explain how solutions are classified as acids or bases. Then,give an example of a weak acid.
QUESTION 10
If you can drink milk as an adult, it means that you have inherited a mutation in the promoter of your lactase gene (the gene that encodes the enzyme you need to break down lactose). Predict the effect of this mutation:
The mutation changes the number of domains in the enzyme, which makes it work more efficiently | ||
The mutation changes the amino acid sequence of the lactase protein | ||
The mutation increases the number of copies of the lactase gene that will be found in your genome | ||
The mutation changes whether the lactase sequence is found in an intron or exon | ||
The mutation affects the expression of the lactase gene |
1.2 points
QUESTION 11
A competitive inhibitor is decreasing the activity of an enzyme. Predict the effect of adding more substrate to the reaction.
The substrate will increase the reaction rate by binding to the allosteric site | ||
The substrate will increase the reaction rate by competing with the inhibitor for the active site | ||
The reaction rate will not change unless the inhibitor can be removed | ||
The enzyme adjusts its shape so that the substrate, but NOT the competitive inhibitor, can bind | ||
The substrate will bind to the competitive inhibitor and block its ability to bind to the enzyme |
1.2 points
QUESTION 12
What determines where in the genome a transcription regulator will bind?
Transcription regulators bind to the 5' UTR region of a gene | ||
Regulators bind via complementary base-pairing to certain DNA molecules | ||
Covalent bonds form between the transcription regulator and the atoms of the DNA backbone | ||
Every eukaryotic gene has a different transcription regulator that will bind to the 5' end of the gene | ||
Transcription regulators bind to specific DNA sequences via multiple weak non-covalent interactions |
1.2 points
QUESTION 13
What is the basic premise of cell theory?
DNA -> RNA -> protein | ||
All cells arise from pre-existing cells | ||
DNA provides the complete instructions to create a cell | ||
The identity of a cell is determined through gene expression patterns | ||
All cells contain the same four basic macromolecules |
1.2 points
QUESTION 14
What is the benefit of using BOTH the lac activator and the lac repressor to control gene expression?
Using both an activator and repressor enables cells to more accurately determine the amount of lactose available in the environment | ||
Enzymes to digest lactose are only made when energy is low and lactose is available | ||
The activator can override the inhibition of the lac operon by the repressor | ||
The repressor can control the enhancer, while the activator can control the promoter | ||
When neither the lac activator or repressor is present, expression of the lac operon is too high |
1.2 points
QUESTION 15
What is the histone code used for?
Phosphorylation and acetylation of DNA affect its ability to be compacted | ||
Changes to the sequence of DNA change whether DNA will wrap around histone proteins | ||
Covalent modifications of histones affect the ability of the transcription initiation complex to form | ||
Histones provide the codon sequences needed for translation to occur | ||
The histone code affects which amino acids will get added to a polypeptide |