Lab Practical

What is the purpose of the second stop when using a micropipette?

What is the purpose of the second stop when using a micropipette?

This is the appropriate ending position for completely dispensing liquid from a micropipette tip

What is the metric system prefix for 10^0

Base Unit

What is the metric system prefix for 10^-3

Milli

What is the metric system prefix for 10^-6

Micro

What is the metric system prefix for 10^-9

Nano

53 mg = How many grams?

0.053g

Calculate the amount of grams of NaCl (58.44 g/mol) to prepare 2000 mL of 3M NaCl solution

350.64Ho

How many moles are in 6L of a 1.5M KOH solution? (56.11 g/mol)

9

The density of 2M NaCl is 1.077 g/mol. How much should 8mL of 2M NaCl weigh (round to 3 decimal places)

8.616

How many moles are in 471 mL of a 2M KOH (56.11 g/mol) solution?

0.942

What is the correct equation for calculation total magnification?

(Ocular mag) * (Objective mag)

You are working with a microscope with 20x ocular lenses and the following objective lenses: 4x, 20x, 400x. Suppose the field of view on this micoscope is 0.5 mm at a total magnification of 400x. Calculate the field of view when using the 4x objective.

2.5

A buffer is made up of:

A weak acid and its conjugate base

Given a stock solution of 8M NaOH, calculate the milliliters of stock solution needed to prepare 1 mL of a 152 mM NaOH solution

0.019

Water has a higher pH of lemon juice. What must be true regarding Water's concentration of hydrogen ions relative to lemon juice?

Water has a lower concentration of hydrogen ions than does lemon juice

What property of water is the basis for the pH scale?

Water self ionizes

What chemical in the reaction is the weak acid? Na₂HPO₄ + H₂O ⇌ NaH₂PO₄ + OH⁻ + Na⁺

NaH₂PO₄

What is the pH of a solution with a concentration of 0.00003871M hydrogen ions?

4.41

Which molecule is more nonpolar?

Acetone is more nonpolar than ethanol

How many polar areas are present that allow water to interact with other polar molecules?

3

Given a stock solution of 9M NaOH, calculate the mL of stock solution needed to prepare 1 mL of a 168 mM NaOH

0.02 mL

Biuret reagent is used in a colorimetric test that can determine protein concentration by spectrophoteometry. Biuret regent specifically reacts with the presence of what?

Peptide bonds

Which test tube is the appropriate blank for a Biuret protein assay?

Tube 2

What reagent was used as an indicator to detect the presence of lipids?

Sudan IV

What reagent was used as an indicator to detect the presence of carbs?

Benedict's Test

What reagent is used as an indicator to detect the presence of nucleic acids?

Ethidium Bromide

What reagent is used as an indicator to detect the presence of proteins?

Biuret reagent

All polysaccharides are this type of sugar

Non-reducing

What type of sugar is glucose?

Monosaccharide (reducing)

What type of sugar is glycogen?

Polysaccharide (non-reducing)

What type of sugar is starch?

Polysaccharide (non-reducing)

What type of sugar is lactose?

Disaccharide (reducing)

What type of sugar is galactose?

Monosaccharide (reducing)

What type of sugar is sucrose?

Disaccharide (non-reducing)

The only non-reducing disaccharide is?

Sucrose

What is bond for nucleic acids?

Phophodiester

What is bond for proteins

Peptide

What is bond for lipids?

Ester

What is bond for carbs?

Glycosidic

What type of sugar is cellulose

Polysaccharide (non-reducing)

Where will a noncompetitive inhibitor bind

Not to the active site

In the enzyme activity exercise, match each reagent to its role

Enzyme sodium diphosphate Product phosphatase Substrate p-nitrophenyl phosphate Inhibitor p-nitrophenyl

Enzyme phosphatase Product p-nitrophenyl Substrate p-nitrophenyl phosphate Inhibitor sodium diphosphate

Select all the correct answers. pH can disrupt the structure of a protein by interfering with? Primary structure Secondary structure Tertiary structure Quaternary structure

Secondary structure Tertiary structure Quaternary structure

T/F Enzymes work by adding energy to the reaction

False

The phosphatase enzyme used in lab consists of a single polypeptide chain. What is the highest level of organization displayed in this phosphatase enzyme?

Tertiary

T/F Phosphatases are a group of enzymes that add a phosphate group from the substrate

False

Why was the base sodium hydroxide added to the enzyme reaction mixture after incubation in the enzyme lab?

To ionize the product, producing a yellow solution

A patient sample was found to contain 0.110 U/mL of alkaline phosphatase. Normal levels of alkaline phosphatase are between 30 and 120 U/L. Is this patient sample within the normal range?

Yes

Digestion by pepsin will create:

Short peptides and amino acids

When swallowing what structure covers the trachea?

EpiglottisW

Food travels down what to the stomach?

Esophagus

This is one of the end products of the reaction catalyzed by lipase

Fatty acid

This reagent was used to detect the end product of the carbohydrate digestion reaction

Benedict-Q

What is the end product of the carbohydrate digestion reaction catalyzed by amylase?

maltose

Contractions of the longitudinal muscle layer in the intestines are responsible for moving food along the digestive tract. What is this process called?

Peristalsis

Enzymatic digestion begins in the mouth with the secretion of which enzyme?

Amylase

What secrets amylase?

Salivary glands

A synthetic cell is made of semi-permeable dialysis tubing and is filled with 10% sucrose. It is placed into a beaker containing 5% sucrose solution. What will happen to the cell?

The cell will gain weight as it takes on water

Diffusion is:

Movement of a molecule from an area of high concentration to an area of low concentration

Urea is able to cross the cell membrane and therefore is a penetrating solute. What are the osmolarity and tonicity of solution with 0.5M Osm Urea? The osmolarity of a cell is 0.3 Osm.

Hyperosmotic, hypotonic

Membranes are made up of many different compounds, like phospholipids, proteins, cholesterol, etc. The ability of these components to move around one another is known as:

Fluid mosaic model

How many grams of solute would you need to make 200mL of 19% (w/v) CaCO3 (100.09 g/mol)?

38

Under the microscope, what did the cells who experienced lysis look like?

They were not there, they burst

Spiky red blood cells are in what state of tonicity?

Crenation

Neutral red is red under acidic conditions and yellow under basic conditions. In the positive control of the membrane integrity experiment, neutral red was added to a solution of yeast suspended in 1% sodium hydroxide. If you were to measure the pH of a solution, it would be basic and yet the solution turns red. Why?

The solution will turn red because neutral red is able to penetrate the cell membrane and the inside of the cell is acidic, even though the cell is in a basic solvent

T/F The maltose transporter is an example of active transport, in which ATP is hydrolyzed in order to move maltose into the cell.

TrueW

What is the substrate in the maltose transporter assay?

pNPalphaG

The maltose transporter protein is what kind of carrier protein?

Symporter

A molecule enters the cell through a transmembrane protein. The cell does not use ATP to import this molecule. What kind of transport is this?

Facilitated diffusion

What are the 3 processes carried out by the nephron?

Filtration, secretion, reabsorption

Smallest functional unit of the lung is called the: and is where gas exchange occurs

Alveoli

The lungs expand when there is an increase or decrease in thoraric cavity?

Increase

The lungs expand when this contracts

Diaphragm

In the aerobic respiration experiment, the dependent variable is best described as?

The amount of light transmitted through DCPIP solution

Where does glycolysis occur in the cell?

Cytoplasm

DCPIP is clear in its _____ state?

Reduced

Sequence the following structures to reflect the branching path of blood through the body beginning with air being taken in (Trachea, bronchi, Alveoli, Larynx, bronchioles, nares)

Nares Larynx Trachea Bronchi Bronchioles Alveoli

Breathing in humans is the result of?

Negative pressure

Where does fermentation occur in the cell?

Cytoplasm

In the fermentation experiments the dependent variable is best described as?

Volume of CO2 gas produced

For the yeast fermentation experiment, a mixture of yeast + glucose + water was incubated in the temperatures listed below. Match temperatures with expected outcome

0 C 22 C 45 C 100C

Maximum CO2 produced, optimal temperature No Co2 produced, limited free energy Small amount of CO2 produced, limited free energy No CO2 produced, proteins denatured

0: No Co2 produced, limited free energy 22: Small amount of CO2 produced, limited free energy 45: Maximum CO2 produced, optimal temperature 100: No CO2 produced, proteins denatured

Based on glycolysis and lactose intolerance, speculate what might cause trehalose intolerance. Lactaid is brand name product which contains the enzyme lactase. Trehalose is a disaccharide produced in some insects as energy storage

The experiments showed glycolysis does not occur significantly without lactase which breaks down lactose. Trehalose intolerance could occur if insects do not posess the proper enzyme to break down trehalose. There is nothing that cleaves the bonds of trehalose. However just like how lactase can be obtained in the form of lactaid, the enzyme that breaks down trehalose can likely be obtained in other ways

Blood is sent from heart to body when muscles of the:

Ventricles contract

Select all answers that are monosaccharides Glucose Fructose Galactose Sucrose

Glucose, Fructose, Galactose

Oxygenated blood travels from lungs to the heart via the:

Pulmonary vein

During PCR, thermal cycler switches between three different temperatures. Match what occurs in the PCR reaction with the appropriate temperature

45C, 60C, 72C, 95C Taq olymerase adds nucleotides to growing chain of replicated DNA Double stranded DNA molecules come apart Primers base pair and bind to their target sequence on DNA template This is not a temperature used in PCR reaction

45C: Not used 60C: Primers base pair and bind to target sequence 72C: Taq polumerse adds nucleotides... 95C: Double stranded DNA comes apart

Determine correct DNA sequence from the mRNA sequence: 3'-GGA-UAC-AGC-AGA-AAU-GCU-UUA-5'

5'-CCT-ATG-TCG-TCT-TTA-CGA-AAT-3'

Transcribe the following DNA sequence to its corresponding mRNA: AAATGCGCTA

UUUACGCGAU

Where does translation occur?

At the ribosomes in the cytoplasm

Gene is performing a DNA extraction but did not recover any DNA. He forgot the step where he was supposed to add the lysis buffer solution. How would this misstep result in a poor recovery of DNA?

Without the lysis buffer, the cells would be intact and the DNA will not be free in solution to be precipitated.

Using mRNA sequence and codon chart pictured below, determine the first amino acid to be produced. You can assume the ribosome attaches directly before the shown nucleotide sequence begins. mRNA sequence: 5'-UCA-AAG-AUG-CUC-GUA-UGA-AGA-CCA-3'

Met

Assuming perfect efficiency, the number of PCR products present in solution doubles after each cycle of a PCR reaction. Given that 2⁵=32, explain why there will be more than 32 copies of PCR product after 5 cycles of PCR.

The PCR begins with multiple copies of the template DNA, so more than one PCR product is produced by the first cycle

What is the function of the lacY gene?

Transports lactose into the cell

Describe how negative regulation of the lac operon is relieved when lactose is encountered. Specifically mention key molecules involved.

Negative regulation is when the repressor Lacl binds to the operator preventing lac expression. Lactose interacts with LacZ (beta-galactosidase) to create allolactose which binds to the repressor causing the repressor not to be able to bind to the operator.

T/F Large DNA molecules travel further than small DNA molecules during electrophoresis

False

In an electrolytic cell type, the anode has a ___ charge?

Positive

What is function of loading dye?

Binds to DNA sample, increasing density

T/F Operons are units of linked genes and their regulatory elements

An induced enzyme produced by cells only in the presence of a specific chemical, called the ___

Inducer

What does the Lacl protein (repressor) physically do to prevent expression of the lac operon?

Binds to the operator, preventing the ribosome from binding or progressing past the promoter.