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BIOLOGY MIDTERM

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Refer to the accompanying figure. If you treated this organelle to remove ONLY the chlorophyll, which label indicates the portion of the organelle that would be most directly affected by this treatment?

a.

A

b.

B

c.

C

d.

D

e.

E

Which of the following is a key component of the cytoskeleton?

a.

DNA

b.

endoplasmic reticulum

c.

microtubules

d.

ribosomes

e.

centrosome

What is the purpose of regulatory proteins?

a.

To defend against foreign invaders

b.

To control the expression of specific genes

c.

To strengthen and protect cells and tissues

d.

To store nutrients

e.

To catalyze a specific chemical reaction

Assume that the shaded portions of the molecule in the accompanying figure each represent different polypeptide chains. What does this represent?

a.

the quaternary structure of a protein

b.

a steroid hormone

c.

a carotenoid

d.

an amino acid

e.

cellulose

What is the primary function of mitochondria?

a.

material storage

b.

transformation of energy

c.

capturing light for photosynthesis

d.

lipid synthesis

e.

protein synthesis

An amino group is weakly basic and includes a(n) ____ atom covalently bonded to two hydrogen atoms.

a.

oxygen

b.

carbon

c.

phosphate

d.

sulfur

e.

nitrogen

Why is ATP important in living organisms?

a.

It is easily converted to starch for long-term storage.

b.

Like all other nucleic acids, it stores hereditary information.

c.

Like RNA, it acts as a source code for the formation of proteins.

d.

It is an important structural component of cell membranes.

e.

It can transfer some of its energy to other chemicals.

Which process is a function of peroxisomes?

a.

cell death

b.

detoxification

c.

water storage

d.

DNA replication

e.

protein synthesis

Golgi complexes of prokaryotic cells produce extracellullar polysaccharides that are used to make cell walls.
__________________

True

False

Plants lack organ systems for disposing of toxic metabolic waste products. Their cells’ vacuoles are like what animal cell organelle?

a.

lysosomes

b.

chloroplasts

c.

endoplasmic reticulum

d.

mitochondria

e.

nucleolus

If a toxin, such as a bacterial toxin, destroys ribosomes, what cellular activity will be affected first?

a.

protein synthesis

b.

active transport

c.

DNA synthesis

d.

movement

e.

energy storage

The outer membrane of the nuclear envelope is continuous with the membrane of the ____ and is usually covered with attached ribosomes.

a.

plasma membrane

b.

endoplasmic reticulum

c.

nucleolus

d.

cell wall

e.

chromatin

Identify three functions of proteins other than enzymes and briefly discuss or describe each.

The following amino acid would be characterized as ____ based on the chemical properties of its side chain.

a.

acidic

b.

basic

c.

hydrophilic

d.

nonpolar

e.

electrically charged

What is the purpose of molecular chaperones?

a.

To transfer an amino acid

b.

To assist the folding of other molecular proteins

c.

To straighten other molecular proteins

d.

To attach a carboxyl group

e.

To strengthen the tertiary structure of a protein

A glycoprotein destined for secretion from the cell would move through the Golgi complex which sequence?

a.

cis face to trans face to medial region

b.

trans face to medial region to cis face

c.

medial face to trans face to cis face

d.

trans face to cis face to medial region

e.

cis face to medial region to trans face

How many carbon sugars are there in a pentose sugar?

a.

two

b.

three

c.

five

d.

six

e.

eight

How does the scanning electron microscope differ from the transmission electron microscope?

a.

The SEM relies on the detection of electrons from the beam after contact with the specimens.

b.

The SEM can view a live specimen.

c.

The SEM gives a three dimensional image of the object being studied.

d.

The SEM can view the internal structure of a cell.

e.

The SEM utilizes a beam of light that passes through the specimen.

A single cell in a smoker’s lung has become cancerous. It doubles its DNA and divides much faster than a normal lung cell. The most likely change that would have caused this condition took place in the:

a.

lysosome.

b.

nucleus.

c.

mitochondria.

d.

microtubule.

e.

nucleolus.

During an infection, white blood cells travel to the infected site and phagocytize the pathogens. After phagocytosis, primary lysosomes fuse with the phagocytic vesicle to form a larger vesicle called a secondary lysosome. The purpose for this process is to:

a.

degrade the bacteria and export it from the cell.

b.

coat the bacteria in lipids derived from the Golgi complex, which cover and smother them.

c.

wrap the pathogen in additional membrane, rendering them harmless.

d.

mix the pathogens with strong hydrolytic enzymes and destroy them.

e.

introduce antibodies to the phagocytic vesicles.

What is the microtubule arrangement of a flagellum or cilium?

a.

9 x1 array

b.

9 x 3 structure

c.

9 + 2 arrangement

d.

9 + 3 arrangement

e.

9 + 1 array

What does the nucleolus, within the nucleus, synthesize?

a.

messenger RNA

b.

genes

c.

hormones

d.

ribosomal RNA

e.

DNA

DNA is associated with RNA and certain proteins, forming a complex called:

a.

chromosomes.

b.

nucleus.

c.

chromatin.

d.

nucleoli.

e.

genes.

The helical coil shape of an α-helix fibrous protein provides what type of property to that protein?

a.

rigidity

b.

strength

c.

elasticity

d.

heat tolerance

e.

water retention

The existence of a separate set of enzymes and DNA molecules in mitochondria and chloroplasts provide support for serial endosymbiosis.
__________________

True

False

Proteins made on ribosomes may be further modified within which organelle?

a.

peroxisomes.

b.

lysosomes.

c.

nucleus.

d.

mitochondria.

e.

Golgi complex.

The force necessary to cause microtubules of cilia and flagella to slide alongside one another is provided through the action of ____ proteins, which derive the energy to perform their work directly from ____ molecules.

a.

kinesin; glucose

b.

dynein; ATP

c.

dynein; ADP

d.

kinesin; ADP

e.

tubulin; ATP

At which level of protein structure are peptide bonds most important?

a.

primary

b.

secondary

c.

tertiary

d.

quaternary

e.

globular

The smooth ER is the primary site for the synthesis of phospholipids and cholesterol needed to make ____.

a.

ribosomes

b.

cell membranes

c.

DNA

d.

hormones

e.

ATP

Which of the following organelles plays an important role in apoptosis, or programmed cell death?

a.

ribosomes

b.

vacuoles

c.

chloroplasts

d.

peroxisomes

e.

mitochondria

Which cellular structure is correctly matched to the role it plays within the cell?

a.

lysosome−powerhouse of the cell

b.

plastids−structural support of the cell

c.

chloroplast−storage of enzymes

d.

Golgi complex−production of energy

e.

centrosome−cell division

The cis face of the Golgi complex is most directly involved in which process?

a.

accepting vesicles from the ER

b.

transporting molecules out of the Golgi

c.

synthesizing proteins

d.

catalyzing the efficient folding of proteins

e.

packaging molecules in vesicles

If you partially hydrogenate oleic acid, the resulting molecule most likely would:

a.

lose a carboxyl group.

b.

contain more double bonds.

c.

lose a carbon atom.

d.

become soluble in water.

e.

have a double bond changed from cis to trans.

What cellular structure is unique to plant cells and some photosynthetic fungi?

a.

vacuoles

b.

mitochondria

c.

endoplasmic reticulum

d.

nucleus

.

Chloroplasts

The accompanying image is the product which type of microscope?

a.

transmission electron microscope

b.

phase-contrast light microscope

c.

Nomarski differential interference microscope

d.

scanning electron microscope

e.

confocal fluorescence microscope

Evidence that all living cells have a common origin is best illustrated by the:

a.

cell theory, which states that the cell is the basic unit of life.

b.

basic similarities in cell structure and chemistry.

c.

idea that cells are the smallest units that can carry out all life activities.

d.

fact that all new cells come from previously existing cells.

e.

fact that cells are the building blocks of the most complex plants.

Glucose and fructose are ____ because they have identical molecular formulas but their atoms are arranged differently.

a.

enantiomers

b.

tertiary

c.

geometric isomers

d.

structural isomers

e.

polar

The largest and most complex assembly of proteins in most eukaryotic cells are the:

a.

flagella

b.

ribosomes

c.

nuclear pores

d.

smooth ER

e.

chromosomes

What organic molecules is the primary structural component of cell membranes?

a.

cellulose

b.

disaccharides

c.

glycogen

d.

phospholipids

e.

adenine triphosphate

What is one cellular characteristic found in all prokaryotic and eukaryotic cells?

a.

plasma membrane

b.

nucleoplasm

c.

mitochondria

d.

nucleus

e.

chloroplast

A molecule of a saturated triacylglycerol contains:

a.

the maximum number of double bonds between carbons in the fatty acid chains.

b.

the maximum number of hydrogen atoms in the fatty acid chains.

c.

fatty acid chains with both amino and carboxyl groups.

d.

the maximum number of triple bonds between carbons in the fatty acid chains.

e.

alternating single and double bonds between carbons in the fatty acid chains.

What carbohydrate energy storage molecule is found in animal liver and muscle cells?

a.

cellulose

b.

starch

c.

a fatty acid

d.

cholesterol

e.

glycogen

What is found between the primary walls of adjacent cells for cells to adhere tightly to one another?

a.

collagen

b.

middle lamella

c.

cytosol

d.

intermediate filaments

e.

secondary cell wall

The primary difference between the amino acids commonly found in proteins is in their:

a.

number of phosphate groups.

b.

number of potassium groups.

c.

R or variable groups.

d.

number of asymmetric carbons.

e.

number of carbonyl groups.

Which organelle can be considered a sorting, processing and packaging center?

a.

vacuole

b.

Golgi complex

c.

endoplasmic reticulum

d.

centrosome

e.

centriole

A basal body anchors what part of a cell?

a.

thylakoid

b.

ribosome

c.

centriole

d.

lysosome

e.

flagellum

What type of microscopy uses a laser to excite fluorophores in just a thin “slice” through a cell?

a.

scanning electron microscopy

b.

phase contrast microscopy

c.

Nomarski differential interference-contrast microscopy

d.

confocal microscopy

e.

fluorescence microscopy

Intermediate filaments are most closely associated with which of the following?

a.

pseudopodia

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