Lab Exam

Question 1

Designing experiments with appropriates control?

Answer 1

Control: An element that remains unchanged

Question 2

What are independent and dependent variables?

Answer 2

Independent Variable: Not influenced by any other variable.
Dependent Variable: Value depends on the other. It’s the one that is influenced.

Question 3

Convert microliters to milliliter and vise versa.

Answer 3

1 milliliter (ml) = 1000.00 microliters (ul)

Question 4

How are Micropipettes used?

Answer 4

Micropipettes used to collect and extract samples.
1. By moving the dial we adjust it to the appropriate volume.
2. Next place a clean tip.
3. Press on the plunger to the first stop and hold it. Then place it inside the solution.
4. Slowly release the plunger to collect and draw the sample.
5. Press the plunger to the first stop. Then to the 2nd stop to release the sample and release the plunger after taking it out of the solution.

Question 5

Significance of the First Stop

Answer 5

The first stop is used to fill the Micropipettes tip.

Question 6

Which axis does x and y values go on?

Answer 6

Independent: x-value
Dependent: y-value

Question 7

Differences between Graphs

Answer 7

Bar Graphs: used to compare measurements between different groups. Not continuous.

Scatter Plot: shows the relationship between two numerical values.

Line graph: use when displaying a change in something over a continuous range.
ex: time is continuous

Question 8

Elements needed for a good graph

Answer 8

independent and dependent variables
Labels for both x and y axis.
Title
Trendline
Equation

Question 9

Explain how to make a standard curve

Answer 9

Graphs of light absorbance vs solution concentration.

Question 10

Trendline to calculate an unknown

Answer 10

Trend-line indicates a linear relationship.

Question 11

Describe how to focus the compound microscope.

Answer 11

To focus a compound microscope use the stage control knob, fine focus, course focus, condenser.
Keep adjusting until it’s clear

Question 12

Important parts of the microscope from the lab.

Answer 12

Ocular lens
Objective lens
Stage
Condenser
Iris diaphragm
Light control Knob
Base Stage Control Knobs
Course focus
Fine Focus

Question 13

Total magnification

Answer 13

Power of objective x Power of Ocular

Question 14

Define field of view and depth of field? How do they change as the magnification changes

Answer 14

Field of view is the amount of specimen you view through the objective. The higher the magnification the lower the field of view gets.
Depth of field the depth that is in focus. Greater thickness greater depth of field
As magnification increases depth decreases.

Question 15

Describe how to make a wet mount. What is the purpose of staining?

Answer 15

A wet mount is made by getting getting a small drop of water and placing on a slide. Then place your sample of cells in the drop and stain it to be able to view the cells in the microscope.

Question 16

Describe what you saw in the animal cell slide. Which organelles are visible?

Answer 16

The organelles more visible were the nucleus, cell membrane, cytoplasm

Question 17

Describe what you saw in a plant cell? What organelles were visible?

Answer 17

Chloroplast and cell wall and nucleus were visible

Question 18

Three shapes of bacterial cells.

Answer 18

Bacillus (Rod shaped)
Cocci (round)
Spirilla (spiral)

Question 19

Differences and similarities between prokaryotic and eukaryotic cells

Answer 19

Prokaryotic cells have no nucleus usually bacteria unicellular cells
Eukaryotes have a nucleus with several membrane bound organelles. Multicellular cell
Similarities: They have a membrane. Both have DNA and ribosomes

Question 20

Describe the proper use of the oil immersion lens

Answer 20

Once we’ve looked at the specimen at the microscope now it’s time to view it in 100x on here we will need a drop of oil on the coverslip and touch the lens with the oil.
At the end clean it with a lens paper

Question 21

Define Diffusion. Osmosis. Hypertonic Hypotonic and Isotonic

Answer 21

Diffusion: moving substances from an area of high concentration to low concentration
Osmosis: the moving of water molecules from an area of high concentration to low concentration. Where solutes are mostly present attracts water molecules
Hypertonic: water moves out the cell causing it to shrivel
Hypotonic: water moves in causing it to burst
Isotonic: water flows in and out

Question 22

How does diffusion work

Answer 22

Moves from an area of high concentration to low concentration according to its concentration gradient

Question 23

How does diffusion occur across the plasma membrane. What are membrane channels used for

Answer 23

Membrane channel can facilitate diffusion by having a hydrophilic center where they are able to cross with no complication polar molecules

Question 24

What is osmolarity?

Answer 24

Osmolarity is a process of measurement of solute concentration

Question 25

Animal/plant cells hypertonic hypotonic and isotonic

Answer 25

Hypertonic: animal lyse. Plants, Detach from the cell wall Hypotonic: Animals burst. Plants, expand the central vacuole helps take excess water Isotonic water in and out perfect

Question 26

What affects diffusion

Answer 26

Temperature, pressure, concentration gradient, and membrane permeability

Question 27

Define enzyme, substrate, product, denaturation

Answer 27

Enzyme: protein that catalyzes Substrate: binds to enzyme Product: material results mostly glucose galactose Denaturation: is the breaking of bonds and the different levels of protein such tertiary quaternary

Question 28

Describe catalytic cycle of an enzyme

Answer 28

The substrate binds to the active site. Causing a change in shape of the enzyme and substrate. The substrate then breaks the chemical bonds of the substrate and the enzyme-product compels is formed.

Question 29

Explain how temperature defines enzymatic activity

Answer 29

Raised temperature speeds up Lowered temperature slows down the reaction

Question 30

Oh affect on enzymatic activity

Answer 30

If the pH changes away from the optimum ph than the reaction rate of an enzyme decreases

Question 31

Denaturation

Answer 31

Covalent bonds break and the primary structure of proteins is ruined

Question 32

Inputs and outputs of cellular respiration and photosynthesis

Answer 32

Cellular respiration Inputs: glucose and oxygen Outputs: water, carbon dioxide, ATP molecules Photosynthesis Inputs: water, carbon dioxide, energy in form of sunlight Outputs: glucose and oxygen

Question 33

Where does each take place in the cell?

Answer 33

Cellular Respiration The cytoplasm and mitochondria Photosynthesis In the mesothelioma chloroplasts

Question 34

What are the different pigments that we learned about?

Answer 34

Chlorophyll a Chlorophyll b Beta-Carotene Xanthophyll

Question 35

How does paper chromatography work?

Answer 35

Technique used for the separation of compounds based on the differential solubity in the stationary phase and mobile phase