lab midterm questions

Question 1

objective

Answer 1

contains lenses to magnify the image

Question 2

Arm

Answer 2

used for a hand grip when carrying the instrument; the other hand should be placed on the base

Question 3

stage

Answer 3

large, flat surface, supports the slide or specimen over the hole that admits light from below

Question 4

coarse-focus knob

Answer 4

changes the distance between the objective lens and specimen to permit rough focusing

Question 5

blue filter

Answer 5

increases resolution by reducing the wavelength of light

Question 6

mechanical stage

Answer 6

holds slide on stage and allows for exact slide manipulation

Question 7

mechanical stage knobs

Answer 7

one knob moves a slide vertically, and the other moves it horizontally

Question 8

fine focus knobs

Answer 8

permits more precise focusing

Question 9

condenser

Answer 9

contains 2 lenses that focus light onto the specimen

Question 10

iris diaphragm

Answer 10

regulates the amount of light passing through the lenses in the condenser. reducing the amount of light increases the visibility of semi-transparent objects

Question 11

condenser adjustment

Answer 11

move the condenser up and down

Question 12

lamp switch

Answer 12

turns the light on and off

Question 13

lamp intensity dial

Answer 13

adjusts the intensity of light bulb

Question 14

stage clips

Answer 14

hold a slide in position over the stage

Question 15

main switch

Answer 15

controls supply of power to scope. must be in the “on” position for either light to work

Question 16

T switch

Answer 16

turns the light below a specimen on and off

Question 17

I switch

Answer 17

turns the light above a specimen on and off

Question 18

on the light microscope, how is the function of the condenser different from the function of the light source?

Answer 18

the condenser focuses the light on the specimen and light source provides the light

Question 19

how does the image appear in the dissecting microscope

Answer 19

right side up, moves the same way you move it

Question 20

how does the image appear in the compound microscope

Answer 20

inverted, upside down and reversed (the left will appear on the right)

Question 21

where can you find the magnifying power of a microscope lens?

Answer 21

it is indicted on the objectives and eyepieces (4x,8x,40x)

Question 22

what is the ‘field’?

Answer 22

the bright circle of light you see when you look through the microscope

Question 23

how do you calculate magnification?

Answer 23

ocular lens x objective lense

Question 24

how do you calculate the actual size of the specimen?

Answer 24

field diameter x fraction of the field occupied by specimen

Question 25

when should you never use the coarse adjustment of the compound microscope?

Answer 25

when you are using the highest power objective lens

Question 26

an organism swims across the high power field(0.4mm) in 16 seconds. how fast is it swimming in um/min?

Answer 26

0.025mm/second so 0.025mm x 60 seconds= 1.5mm/second -->1.5x100um= 150 um/ minute

Question 27

an object stretches across 1/5 of the low power field (4.5mm). you draw it 6.3cm long. what is the magnification of your drawing?

Answer 27

1/5x 4.5mm= 0.9mm | 6.3/0.9mm= 7mm

Question 28

an object occupies 2/3 of the high power field(0.45mm). you are told to draw it magnified 660x. what will be the length of you drawing?

Answer 28

2/3x0.45= 0.3mm | 0.3x 660= 159mm

Question 29

what are the 5 steps in a scientific method

Answer 29

``` observation question hypothesis prediction test ```

Question 30

what is a hypothesis?

Answer 30

reasonable explanation for observed phenomenon.

Question 31

can a hypothesis be proven? explain your answer.

Answer 31

no because you would have to prove it in every possible way

Question 32

what happens if a hypothesis is rejected?

Answer 32

the null hypothesis is accepted

Question 33

distinguish between the experimental test and control test

Answer 33

the experimental test receives the single variable being tested and the control does not

Question 34

what is the purpose of the control test?

Answer 34

to minimize the effects of variable other than the independent variable to compare it to the experimental test

Question 35

what is the purpose of replicating your tests?

Answer 35

to decrease the likelihood that the observed results are due to chance and increase the likelihood that the results are the response to the environmental conditions

Question 36

null hypothesis

Answer 36

a statement that the study subjects have no preference for the environmental conditions of the variable you are testing

Question 37

alternate hypothesis

Answer 37

a statement that suggests that the subjects do have a presence for one environmental condition over another. but does not indicate which environmental choice might be preferred

Question 38

list 5 abiotic variables that could affect animals in their natural habitat

Answer 38

``` temperature water/ moisture sunlight wild soil type ```

Question 39

difference between compound and dissecting microscope

Answer 39

compound works by letting light pass through the specimen and a sequence of lenses to magnify the image dissecting used for dissecting specimen, not as powerful as compound

Question 40

DNA stands for

Answer 40

deoxyribonucleic acid

Question 41

DNA is a polymer of

Answer 41

nucleotides

Question 42

Each DNA nucleotide is made of what 3 units?

Answer 42

a five-carbon sugar ring (deoxyribose), a phosphate group nitrogenous base

Question 43

4 Nitrogenous bases in DNA

Answer 43

Guanine Adenine Cytosine Thymine

Question 44

what are the 2 nitrogenous base groups

Answer 44

Purines - has 2 rings | Pyrimidines - has 1 ring

Question 45

define phosphodiester bond

Answer 45

nucleotides joined together via bond between the sugar of one nucleotide and the phosphate group of another

Question 46

positive control

Answer 46

something that will give a positive reaction. (positive control for starch is a starch solution)

Question 47

negative control

Answer 47

something that will give a negative reaction. (negative control for starch is water)

Question 48

what is a test for starch and what colour does it turn?

Answer 48

iodine, blue- black colour

Question 49

what is a reducing sugar test with? what colour does it turn?

Answer 49

Benedict's, green, yellow, red or brown

Question 50

test for proteins? what colour does it turn?

Answer 50

Biuret test, violet colour

Question 51

test for lipids? what colour?

Answer 51

sudan IV, pink or red

Question 52

Acid Hydrolysis

Answer 52

macromolecules break down into monomers in the presence of heat and acid

Question 53

distinguish between resolution and magnification

Answer 53

resolution refers to the clarity of an image (distinguishing two objects from one another) , magnification refers to the ability to make small objects seem larger

Question 54

what is the relationship between magnification and the depth of field?

Answer 54

the higher the magnification the smaller the depth of field

Question 55

the vertical distance that remains in focus at each magnification is called

Answer 55

depth of field

Question 56

describe 2 ways to improve the resolution of the light microscope

Answer 56

blue filter improves resolution by reducing the wavelength of light that enters the condenser resolution can also be improved by adding immersion oil

Question 57

describe 3 ways to improve contrast of a specimen

Answer 57

adjust the condenser reducing the amount of light using the iris diaphragm using artificial dyes

Question 58

what is contrast

Answer 58

a quality that makes the image stand out better

Question 59

what is the pH scale used for

Answer 59

a way of describing the concentration of H+ ions in a water solution