a3

What is the correct order of occurrence for the steps of protein synthesis

1. mRNA is produced in nucleus. 2. Ribosome moves along mRNA. 3. DNA uncoils for transcription. 4. Polypeptide is produced. 5. tRNA brings amino acids to ribosome. 6. mRNA moves to ribosome. A) 3, 1, 6, 2, 5, 4

What part of the plasma membrane is hydrophobic?

3

What would be an example of a cell maintaining homeostasis at the cellular level

A cell takes up potassium to maintain the proper cytoplasmic potassium concentration

The anticodon for the triplet UCA is

AGU

Which of the following statements about the Golgi apparatus is false?

B) It sends transport vesicles to the RER

The following is a list of the steps involved in the process of secretion by the Golgi apparatus. What is the proper order for these steps?

D) 3, 5, 6, 1, 4, 2

Chromosomes consist of ________ and ________.

DNA; proteins

The cell theory includes all of these concepts except

Every cell is capable of living and on its own if isolated from the body

The ________ typically consists of five or six flattened membranous discs called cisternae.

Golgi apparatus

What is the source of new material for the plasma membrane?

Golgi apparatus

The extracellular fluid in most tissues is called blank fluid

Interstitial

What is an advantage of the electron microscope over the compound light microscope

It allows much greater magnification of a specimen

How is the plasma membrane involved in structural support of body tissues?

It has specialized connections to other cells or extracellular materials

If a hole is torn in a cell's plasma membrane, the cell will die because

It will not be able to maintain differences between the cytoplasm and extracellular fluid

________ are compartments within the cell whose contents are isolated from the cytosol

Membranous organelles

The only kind of cell in the body that is not produced by the division of preexistí get cells is

None, because every cell is produced by the division of another cell

Most cells have only one

Nucleus

What is a structure that separates the contents of a human cell from its surrounding medium

Plasma membrane

________ are responsible for identifying and digesting damaged or denatured proteins.

Proteasomes

The enzyme ________ is required for the synthesis of mRNA

RNA polymerase

________ may be scattered in the cytoplasm or bound to endoplasmic reticulum.

Ribosomes

If the amount of chloride ion in blood plasma increases, which of the following would initially occur?

The blood osmotic pressure will increase

Which of the following statements concerning mitochondria is false?

The mitochondria produce oxygen in the process of energy transformation

What is the first part of the cell that is affected when the ph of extracellular fluid changes

The plasma membrane

Cytology is the study of

The structure and function of cells

Imagine a beaker divided down the center by a rigid membrane that is freely permeable to water but impermeable to glucose. Side 1 contains a 10 percent glucose solution and side 2 contains the same volume of pure water. At equilibrium, what will be the situation?

The volume of liquid will be greater in side 1.

How do chromosomes become visible under a light microscope as a cell prepares to divide?

Thin strands of chromatin coil tightly and then coil again.

The mRNA sequence that is complementary to the sequence ATC on DNA is

UAG

Compared to the extracellular fluid, cytosol contains

a higher concentration of potassium ions.

Most of the surface area of a plasma membrane consists of

a phospholipid bilayer.

In addition to secreting products from the cell, vesicles produced by the Golgi apparatus can

add new material to the plasma membrane

Microfilaments

anchor the cytoskeleton to integral proteins of the cell membrane.

During protein synthesis, amino acids are assembled in the proper sequence because each tRNA has a(n) ________ that binds to the next codon in the mRNA.

anticodon

Proteins of the plasma membrane carry out all of the following functions except

binding to DNA to turn on genes.

Peroxisomes

both generate and break down hydrogen peroxide.

Proteosomes ________ proteins that have been damaged or denatured.

break down

A mature red blood cell lacks a nucleus; therefore, it

cannot make new proteins and will be worn out within a few months

Identify the mismatched pair.

carrier proteins—allow a cell to move

The smallest living unit within the human body is

cell

Some cells contain large numbers of mitochondria while others have relatively few or none. This suggests that

cells with large numbers of mitochondria have a high energy demand

The ________ is the microtubule organizing center of the cell.

centrosome

Water molecules and small ions enter a cell through

channels formed by integral membrane proteins

In cells that are not dividing, chromosomes uncoil to form a tangle of fine fibers known as

chromatin

Which of following properties of the cytoskeleton is incorrect?

connects cells to each other

Which of the following descriptors regarding cytoplasm is false?

contains less protein than extracellular fluid

In ________, one substance is transported into the cell and another is transported out.

countertransport

The watery component of the cytoplasm is called

cytosol

Which of the following is false about DNA fingerprinting?

determined by analyzing proteins

The movement of oxygen from an area of high concentration to an area of low concentration is an example of

diffusion

Which of the following best describes osmosis?

diffusion of water from a greater to a lesser water concentration across a selectively permeable membrane

When activated, lysosomes function in

digestion of materials

There is a direct correlation between the potency of a general anesthetic such as ether and its ability to

dissolve in lipids.

Microfilaments do not

distribute chromosomes to opposite ends of a dividing cell.

If an animal cell lacked centrioles, it would not be able to

divide.

Before the mRNA transcribed from a gene can be used to translate into a protein, it must be

edited to remove introns and transported into the cytoplasm

Many proteins in the cytosol are ________ that accelerate metabolic reactions

enzymes

Assume that the import of a particular amino acid across the plasma membrane is observed (1) to occur only down its concentration gradient and (2) to slow when a different but similar amino acid is added to the extracellular fluid. The movement of the amino acid through the membrane is most likely by

facilitated diffusion

The process by which molecules such as glucose are moved into cells along their concentration gradient with the help of membrane-bound carrier proteins is called

facilitated diffusion.

Centrioles form the basal bodies that anchor microtubules within cilia and

flagella.

The functional units of DNA that contain the instructions for making one or more proteins are

genes.

The endoplasmic reticulum is responsible for all of the following except

housing the chromosomes

The tails of a phospholipid molecule in a plasma membrane are

hydrophobic.

A blood cell undergoes crenation when it is placed in a(n) ________ solution

hypertonic

A solution that contains a lower osmotic pressure than the cytoplasm of a cell is called

hypotonic

Hemolysis may occur when a blood cell is placed into a(n) ________ solution.

hypotonic

Masses of insoluble material that are sometimes found in cytosol are known as

inclusions.

Microvilli are found on cells of the inner surface of the small intestine, where they

increase the absorption of nutrients from digested food

A patient suffers blood loss and is given IV fluids that contain an impermeable carbohydrate called dextran, which serves to ________ leading to an increase in blood volume.

increase the osmolarity of the blood

A gene is a set of specific instructions that

indicates the sequence of amino acids in a protein molecule

Which of following properties of microtubules is correct?

interact with dynein and kinesin

Receptor molecules on the surface of cells bind specific molecules called, in general

ligands.

Macrophages are cells that engulf and consume germs or debris. What organelle must be especially plentiful in these cells?

lysosomes

Each of the following is an example of a nonmembranous organelle except

lysosomes.

A molecule of ________ contains all the codons needed to produce a particular polypeptide.

mRNA

Water and small hydrophilic solutes

may pass through channels in the plasma membrane

A cell can increase how fast a substance diffuses across its plasma membrane by inserting channels, which modify the

membrane's permeability to the substance

The endoplasmic reticulum is an example of a(n) ________ organelle.

membranous

The "m" in mRNA stands for

messenger.

Tubulin is to microtubules as actin is to

microfilaments.

Cilia and flagella contain nine pairs of ________ surrounding a central pair.

microtubules

Which of the following cytoskeleton components moves the chromosomes during cell division?

microtubules

Most of the ATP required to power cellular operations is produced in the

mitochondria

Breathing faster and deeper eliminates more carbon dioxide from the body than normal breathing. Under these circumstances, in the lungs

more carbon dioxide will diffuse out of the blood

Permanent alterations in a cell's DNA that affect the nucleotide sequence of one or more genes are called

mutations.

The nucleus is surrounded by the

nuclear envelope.

Transfer of mRNA from the nucleus to the cytosol occurs through

nuclear pores

The components of ribosomes are formed within

nucleoli

Which organelle is more prominent in cells that make large amounts of protein?

nucleolus

Histones are found in

nucleosomes

Most of a cell's DNA is located in its

nucleus.

The control center for cellular operations is the

nuclues

Each triplet of bases in a gene corresponds to

one amino acid in a protein

The cytoplasm contains the fluid cytosol, insoluble inclusions, and the

organelles.

The ________ of a cell membrane indicates how easy it is for substances to cross

permeability

Organelles that break down fatty acids and hydrogen peroxide are

peroxisomes.

The start of each gene begins with a(n) ________ segment.

promoter

Motile cilia move fluids across a cell's surface, while a flagellum

propels a cell through fluid.

mRNA is needed to synthesize ________ in the cytoplasm

proteins

Ribosomes are composed of protein and

rRNA.

Identify the role of cholesterol in the plasma membrane.

reduces membrane fluidity and permeability

The duplication of DNA is called ________, the copying of DNA to mRNA is called ________, and the reading of the mRNA by the cell to make a protein is called ________.

replication; transcription; translation

The "r" in rRNA stands for

ribosomal.

Which form of endoplasmic reticulum modifies and packages newly synthesized proteins?

rough endoplasmic reticulum

Which of the following consists of a network of intracellular membranes with attached ribosomes?

rough endoplasmic reticulum

Cell membranes are said to be ________ because they allow some substances to pass but not others.

selectively permeable

The plasma membrane does not include

silk mesh.

Synthesis of lipids and glycogen takes place at the

smooth ER.

Blank cells are all of the cells of the body except the reproductive cells (sperm and oocytes)

somatic

Examination of a sample of glandular cells reveals an extensive network of smooth endoplasmic reticulum. Which of the following is the likeliest product of these cells?

steroid hormones

Which of the following is not a function of membrane proteins?

store cellular nutrients

Each of the following is a function of smooth endoplasmic reticulum except

synthesis of protein.

Amino acids are transferred to the ribosome to be incorporated into a growing polypeptide chain by

tRNA.

Diffusion of a substance across the cell membrane may be influenced by all of the following except

the availability of ATP.

If the concentration of sodium chloride in the interstitial fluid surrounding cells decreases and the concentration of other solutes remains constant,

the cells will swell.

facilitated diffusion differs from ordinary diffusion in that

the rate of facilitated diffusion is limited by the number of available carrier proteins

Functions of the plasma membrane include all of the following except

thermal insulation.

The process of forming mRNA is called

transcription.

The "t" in tRNA stands for

transfer.

The process of protein formation directed by mRNA is called

translation

Thymine is replaced by which nitrogen base in RNA?

uracil