BIOLOGY 2B03 Lecture Notes - Lecture 3: Spindle Apparatus, Fusion Gene, Sickle-Cell Disease

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1 Sep 2020

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To look at anything smaller than a fifth of a millimeter, an image of the object must be magnified. If something is smaller than a mm, then we need to use a microscope. Light microscopes use light (visible) to illuminate the object being studied. Allows us to visualize most prokaryotic cells and organelles inside eukaryotic cells. Anything less than 100 nm needs to be seen under an electron microscope. Visualize small bacteria, viruses, protein complexes, ribosomes, large proteins, lipids or some small molecules. Resolution (d) in microscopy is a measure of the minimum distance between two objects at which the object still appear distinct. Smaller value of d means the resolution is better and more details can be observed. Formula of resolution depends on two variables: wavelength of illuminating light and numerical aperture (na) Wavelength of length: smaller wavelengths of light give higher resolution.

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QUESTION 4

A substance that reacts the same to light polarized in any direction is _________________.

	a.	an isotope
	b.	anisotropic
	c.	isotropic
	d.	divergent

QUESTION 5

The part of the comparison microscope that allows the examiner to view two objects simultaneously is called the _________________.

	a.	comparator
	b.	comparison bridge
	c.	spectroscope
	d.	stage

QUESTION 6

A stereo microscope can best be described as _____________________.

	a.	Two compound microscopes aligned so that they each see a slightly different part of an object.
	b.	Two compound microscopes aligned with a comparison bridge.
	c.	A compound microscope with two separate stages and one ocular.
	d.	A compound microscope with two eyepieces and a camera mount.

QUESTION 7

In microscopy, resolution is a measure of ________________.

	a.	The ability of the lenses to separate two tiny details that are close together.
	b.	The total magnification power of the microscope.
	c.	The empty magnification power of the microscope.
	d.	The ability of an electron microscope to determine the presence of a large number of elements.

QUESTION 8

Two polarizers (polarizing filters) aligned 90Â° from each other will block out all light.

True

False

QUESTION 9

A simple convex lens creates a magnified real image of an object.

True

False

QUESTION 10

A trinocular microscope has three objective lenses mounted on a turret.

True

False

QUESTION 11

Liquids and gases are usually isotropic.

True

False

QUESTION 12

Match each of the following terms with Its Definition

Compound microscope a. Has a polarizer and an analyzer

Electron microscope b. Permits viewing two objects at once

Stereomicroscope c. Consists of a single convex lens

Comparison microscope d. Long working distance, three-dimensional

Simple hand magnifier e. Basic 2 convex lens microscope

Polarizing microscope f. Can magnify images more than 100,000 times

limecheetah620

QUESTION 1

The ocular of a compound microscope has a magnification of 10x and the objective has a magnification of 10x. The total magnification of the microscope is ___---

	a.	10x
	b.	20x
	c.	100x
	d.	1000x

QUESTION 2

The part of the microscope that focuses the light on an object is the ___________.

	a.	Iris Diaphragm
	b.	Coarse Focus
	c.	Condenser
	d.	Body Tube

QUESTION 3

The polarizing filter in a PLM that is located above the objective is called the _________________.

	a.	Polarizer
	b.	Analyzer
	c.	Abbe condenser
	d.	Iris

QUESTION 4

A substance that reacts the same to light polarized in any direction is _________________.

	a.	an isotope
	b.	anisotropic
	c.	isotropic
	d.	divergent

QUESTION 5

The part of the comparison microscope that allows the examiner to view two objects simultaneously is called the _________________.

	a.	comparator
	b.	comparison bridge
	c.	spectroscope
	d.	stage

1 points

QUESTION 6

A stereo microscope can best be described as _____________________.

	a.	Two compound microscopes aligned so that they each see a slightly different part of an object.
	b.	Two compound microscopes aligned with a comparison bridge.
	c.	A compound microscope with two separate stages and one ocular.
	d.	A compound microscope with two eyepieces and a camera mount.

QUESTION 7

In microscopy, resolution is a measure of ________________.

	a.	The ability of the lenses to separate two tiny details that are close together.
	b.	The total magnification power of the microscope.
	c.	The empty magnification power of the microscope.
	d.	The ability of an electron microscope to determine the presence of a large number of elements.

QUESTION 8

Two polarizers (polarizing filters) aligned 90Â° from each other will block out all light.

True

False

QUESTION 9

A simple convex lens creates a magnified real image of an object.

True

False

QUESTION 10

A trinocular microscope has three objective lenses mounted on a turret.

True

False

QUESTION 11

Liquids and gases are usually isotropic.

True

False

QUESTION 12

Match each of the following terms with Its Definition

Compound microscope a. Has a polarizer and an analyzer

Electron microscope b. Permits viewing two objects at once

Stereomicroscope c. Consists of a single convex lens

Comparison microscope d. Long working distance, three-dimensional

Simple hand magnifier e. Basic 2 convex lens microscope

Polarizing microscope f. Can magnify images more than 100,000 times

maroonmuskrat824

__________ are fairly small organelles that provide a safe place within the cell to carry out certain biochemical reactions that generate harmful, highly reactive oxygen species. These chemicals are both generated and broken down in the same location.

Lysosomes

Endosomes

Peroxisomes

Nucleosomes

Biologists cannot possibly study all living species. Instead, they try to understand cell behavior by studying a select subset of them. Which of the following characteristics are useful in an organism chosen for use as a model in laboratory studies?

rapid rate of reproduction

all of the above

ability to grow under controlled conditions

amenability to genetic manipulation

By definition, prokaryotic cells do not possess __________.

ribosomes.

a nucleus.

membrane bilayers.

replication machinery.

Cell biologists employ targeted fluorescent dyes or modified fluorescent proteins in both standard fluorescence microscopy and confocal microscopy to observe specific details in the cell. Even though fluorescence permits better visualization, the resolving power is essentially the same as that of a standard light microscope because the resolving power of a microscope is limited by the __________ of light.

intensity

absorption

wavelength

filtering

Choose the phrase that best completes this sentence: Microtubules ____________ and are required to pull duplicated chromosomes to opposite poles of dividing cells.

generate contractile forces

can rapidly reorganize

are found in especially large numbers in muscle cells

are intermediate in thickness

Despite the differences between eukaryotic and prokaryotic cells, prokaryotes have proteins that are distantly related to eukaryotic actin filaments and microtubules. What is likely to be the most ancient function of the cytoskeleton?

cell division

cell motility

vesicle transport

membrane support

DNA and RNA are different types of nucleic acid polymer. Which of the following is true of DNA but not true of RNA?

It contains thymine.

It has 5'-to-3' directionality.

It is single-stranded.

It contains uracil.

Double covalent bonds are both shorter and stronger than single covalent bonds, but they also limit the geometry of the molecule because they ____________________.

prevent additional bonds from being formed with the bonded atoms.

limit the rotation of the bonded atoms.

create a new arrangement of electron shells.

change the reactivity of the bonded atoms.

Drosophila melanogaster is a/an __________. This type of animal is the most abundant of all animal species, making it an appropriate choice as an experimental model.

mammal

amphibian

bird

insect

10.

If the isotope 32S has 16 protons and 16 neutrons, how many protons, neutrons, and electrons will the isotope 35S have, respectively?

16, 19, 17

16, 19, 15

16, 19, 16

16, 20, 15

11.

Living systems are incredibly diverse in size, shape, environment, and behavior. It is estimated that there are between 10 million and 100 million different species. Despite this wide variety of organisms, it remains difficult to define what it means to say something is alive. Which of the following can be described as the smallest living unit?

cell

organelle

protein

DNA

12.

Macromolecules in the cell can often interact transiently as a result of noncovalent interactions. These weak interactions also produce stable, highly specific interactions between molecules. Which of the factors below is the most significant in determining whether the interaction will be transient or stable?

the concentration of each molecule

the size of each molecule

surface complementarity between molecules

the rate of synthesis

13.

Many of the mechanisms that cells use for maintenance and reproduction were first studied at the molecular level in bacteria. Which bacterial species had a central role in advancing the field of molecular biology?

E. coli

S. pombe

C. elegans

D. melanogaster

14.

Many types of cells have stores of lipids in their cytoplasm, usually seen as fat droplets. What is the lipid most commonly found in these droplets?

cholesterol

isoprene

triacylglycerol

palmitic acid

15.

Mitochondria contain their own genome, are able to duplicate, and actually divide on a different time line from the rest of the cell. Nevertheless, mitochondria cannot function for long when isolated from the cell because they are __________________.

anaerobes.

viruses.

parasites.

endosymbionts.

16.

Mitochondria perform cellular respiration, a process that uses oxygen, generates carbon dioxide, and produces chemical energy for the cell. Which answer below indicates a correct pairing of material âburnedâ and the form of energy produced during cellular respiration?

17.

Polar covalent bonds are formed when the electrons in the bond are not shared equally between the two nuclei. Which one of these molecules contains polar bonds?

BIOLOGY 2B03 Lecture Notes - Lecture 3: Spindle Apparatus, Fusion Gene, Sickle-Cell Disease

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