Cells, mitosis, review of POB lecture quiz

Which of the events could produce new combinations of alleles of genes along a chromosome if crossing over happened during prophase I of meiosis?

crossing over between non-sister chromatids of homologous chromosomes

The plasma membrane is composed of a phospholipid bilayer and associated proteins. What else is commonly found in the plasma membranes of animal cells?

cholesterol

The association of individual water molecules with other water molecules is called _____ and occurs through _____ bonds between water molecules.

cohesion; hydrogen

Which type of cell signaling does not rely on the diffusion of a chemical signal molecule?

contact-dependent signaling

An increased heart rate caused by the release of adrenaline from the adrenal glands, which are located just above the kidney, is an example of _____ signaling.

endocrine

Nails are formed by the _____ layer.​

epidermal

Which one of the steps would occur last as part of the scientific inquiry?

experimentation

Which of the events are listed in the correct order of G protein-coupled signaling?

Adenylyl cyclase catalyzes the formation of cAMP, which activates protein kinase A (PKA).

Which statement is true about the presence or absence of plasma membranes?

All cells have a plasma membrane.

What are the three main parts of a cell.

plasma membrane, cytoplasm, genetic material

The unique properties of water are due to the _____ of water molecules and the ability of water to form _____ with other water molecules and with other polar molecules.

polarity; hydrogen bonds

Colchicine is a drug that blocks the assembly of microtubules. If dividing cells are treated with colchicine, at what stage of mitosis would you predict the arrest would occur?

prophase

The correct sequence of steps in the M phase of the cell cycle is:

prophase, prometaphase, metaphase, anaphase, telophase, cytokinesis.

Which particles are pumped across the lysosomal membrane by a transport protein to create a special internal environment in the lysosome?

protons

A hypothesis is considered a theory when the:

results of several experiments support the hypothesis.

The correct sequence of steps in the eukaryotic cell cycle is:

G1 → S phase → G2 → mitosis → cytokinesis.

Which is NOT true about hair?

Hair color is not influenced by hormones nor the environment.

What is NOT true about hair for humans?

Hair is made of hard keratin. wrong\ Hair is found everywhere on the body.

Which of the statements is true about gamete formation in mammals?

In female gamete formation, the separation of the cytoplasm is unequal during meiosis.

What type of cells are the simplest organisms with a plasma membrane but without a nucleolus?

Prokaryotic Cells

When a ligand binds to a G protein-coupled receptor, which of the answer choices would you expect to happen before any of the others?

Adenylyl cyclase activity increases.

Transcription is the process by which:

RNA is synthesized from DNA.

______ are RNA-protein complexes composed of two subunits that join and attach to messenger RNA.

Ribosome

Which is the correct order of layers of skin from deep to superficial?

Stratum Basale, Stratum Spinosum, Stratum Granulosum, Stratum Lucidum, Stratum Corneum

You observe a cell that has a receptor protein that binds a signaling molecule that is produced by the same cell. What kind of signaling is occurring in this cell?

autocrine signaling

The sodium-potassium pump is an example of:

an antiporter

In order for phospholipids to form bilayers spontaneously in an aqueous environment, the pH should be:

approximately neutral.

When T cells in your immune system recognize a pathogen, they release Interleukin 6 (IL6), which binds back to receptors on the T cell surface. Which of the answer choices best describes this kind of IL6 signaling?

autocrine signaling

What are the layers of the Dermis called?

papillary and reticular

Communication between neurons is an example of which type of cell signaling?

paracrine signaling

_______ is diffusion of a substance across a membrane with no energy investment.

passive transport

The amount of water lost through the skin is almost _____ milliliters a day.​

​500

The number-one way to prevent the spread of disease is _____.​

​handwashing

Consider the image. If the ostrich egg shown in the photo is not fertilized, it is composed of approximately how many cells?

1

In a solution that has pH = 7.0, the ratio of protons (H+) to hydroxide ions (OH-) equals

1

Which number represents the pH of a solution with the highest concentration of hydrogen ions?

1.0

Which choice most accurately describes the ratio of oxygen to carbon to hydrogen in a simple 6-carbon sugar such as glucose?

1:1:2

It is estimated that there are a total of 245 cells (roughly 50 trillion) in the adult the human body. Starting from a fertilized egg, how many cell divisions would be required to produce 245, assuming that every cell divides in every cycle?

45 divisions

_______ is diffusion of a substance across a membrane using energy (from ATP) to move a substance against it natural tendency (up a concentration gradient)

Active transport

A cellular response to a signal can be terminated by:

All of these choices are correct

Phospholipids spontaneously form a variety of structures in aqueous solution. Which choice best describes this property?

All of these choices are correct

Sexual reproduction results:

All of these choices are correct.

The high variability in the cell-specific expression of different types of G protein-coupled receptors, each with a distinct affinity for specific signaling molecules allows:

All of these choices are correct.

To have communication between cells, you must have a:

All of these choices are correct.

How are steroid hormone receptors and cell-surface receptors similar?

Both types undergo a conformational change when they bind to their ligand.

Which molecule would most likely require a transport protein to cross the plasma membrane of a red blood cell?

C6H12O6

According to the figure, what is a key difference between cell signaling by a cell-surface receptor and cell signaling by an intracellular receptor?

Cell-surface receptors typically bind to signaling molecules that are smaller than those bound by intracellular receptors. wrong Cell-surface receptors bind polar signaling molecules; intracellular receptors bind nonpolar signaling molecules.

Which of the statements is correct about cells in G1 phase in the cell cycle?

Cells in G1 phase that do not activate the enzymes associated with DNA synthesis for long periods are said to be in G0 phase.

Actin microfilaments and tubulin-based microtubules are important components of the cytoskeleton that function during mitosis. Which process of cell division would be most affected if actin function was blocked?

Cytokinesis would not occur to divide the cytoplasm.

When it comes to burns, which result is most life-threatening?

Dehydration

_______ is where the plasma membrane envelops small particles or fluid, then seals on itself to form a vesicle or vacuole which enters the cell.

Endocytosis

Which is NOT a part of a phospholipid

Extra cellular fluid

Which is True when it comes to skin color?

Melanin passes from melanocytes to keratinocytes in the stratum spinosum. wrong Skin color is determined by the number of melanocytes in the skin. wrong

______ is the surface of nucleus bound by two phospholipid bilayer membranes.

Nuclear Envelope

Of the answer choices, what is the most likely reason that paracrine signaling does not activate the cell that is producing the signaling molecule?

The cell does not have the proper receptor.

Flexion creases on the skin stem from what?

The network of reticular fibers elevate the dermal layer lying above them. wrong

Why do the functions of many receptor kinases depend on the fluid nature of the plasma membrane?

The receptor monomers must move together and dimerize to be activated.

You strip off all proteins on the cell surface by using a protease (an enzyme that destroys proteins). Now, when you add a specific signaling molecule, the cell still responds. What is the most reasonable explanation of this?

The signal can directly activate the second messenger system and does not need to activate the receptor. wrong The receptor for this signal is inside the cell, and the signaling molecule is nonpolar and can diffuse into the cell.

How would signaling be affected if a mutation caused a G protein to replace GDP with GTP on its own without needing to be activated by the G protein-coupled receptor?

The signaling pathway would be activated even when no ligand was present.

Which answer is NOT true?

The steroid cholesterol effects the fluidity of the animal cell membrane. wrong answer One function of the cell membrane is to regulate the passage of substances into and out of cells and between cell organelles and cytosol. wrong

What is NOT a part of the ABCs of evaluating skin growths for possible Melanoma?

The symmetry of the growth. wrong

An explanation supported by a large body of observations and experimentation is referred to as a(n):

Theory

Which one of the statements explains a characteristic of both all living organisms and all nonliving material?

They both conform to the basic laws of chemistry and physics.

Which statement about first-degree burns is true?

They go through the epidermis only.

____ span the length of the plasma membrane of cells

Transmembrane Proteins

A drug designed to inhibit the response of cells to the steroid testosterone would almost certainly result in which of the answer choices?

a decrease in the transcription of certain genes

Which of the answer choices would be considered a cell-surface receptor?

a protein that forms a channel that allows ions to enter the cell when a ligand binds

Which choice is considered an integral membrane protein?

a protein with its amino-terminus in the cytoplasm and its carboxy-terminus in the extracellular space

A protein on a cell surface that binds to a signaling molecule is an example of which element of cellular communication?

a receptor protein

Which of the answer choices would be found in the cytoplasm and not on the cell surface?

a receptor that binds a nonpolar steroid hormone and activates transcription

What is a hypothesis?

a tentative explanation that can be tested by experiments

Carbohydrates and proteins are two types of macromolecules. Which functional characteristic of proteins distinguishes them from carbohydrates?

ability to catalyze biochemical reactions

The plasma membranes of some plant cells use transport proteins to move protons out of the cell against their concentration gradient. This is an example of:

active transport.

Which type of receptor undergoes a conformational change upon activation?

all of these are correct

When we say that the cell is the fundamental unit of life, we mean that:

all of these choice are correct

Defects in cell signaling can lead to a cancerous cell as a result of:

all of these choices are correct

The extent and duration of a cellular response to a signal depend on the:

all of these choices are correct

Which is a step in cell signaling?

all of these choices are correct

Which statement is true about G proteins?

all of these choices are correct

The type of cellular response to a signal depends on:

all these choices are correct

Despite their differences, steroid hormones:

bind intracellular receptors to form complexes that enter the nucleus.

Some diseases result from defective transport across the membrane. For example, cystic fibrosis results when a chloride ion transporter does not function. What is affected when this transporter does not function?

both the chloride concentration gradient and the electrical gradient of the cell

The cytoskeleton of a cell is made of all of these EXCEPT _____?

centrioles wrong maybe enzyme

Which sequence accurately describes the path traveled by a new protein from when it first starts to be translated to its release from the cell?

cytosol → ER → Golgi → vesicle → plasma membrane → external environment

The beaker in the illustration contains two solutions of salt with different concentrations (measured by molarity, M). The two solutions are separated by a membrane that is permeable to water but not to salt.

diffusion of water from B to A and of salt from A to B wrong diffusion of both water and salt from B to A wrong diffusion of salt from B to A, but not of water maybe

At the end of mitosis, the daughter cells are _____, whereas at the end of meiosis the daughter cells are _____.

diploid; haploid

Which is the most numerous type of sweat gland?

eccrine

The protein-assisted movement of a polar molecule across the membrane that does not require ATP or the input of energy occurs through:

facilitated diffusion

During meiosis, two rounds of DNA synthesis are required to form four gametes from one parent cell.

false

Hyperthermia means having a body temperature below normal.​

false

Hypotheses can only be tested by doing experiments.

false

Interphase is typically the shortest of the two stages of the cell cycle.

false

Purified phospholipids mixed in water will only form membranes if the appropriate enzyme is present.

false

The M phase consists of two events: prophase and cytokinesis.

false

The dermis is the outermost layer of the skin.​

false

Which component of a phospholipid is found in the interior of a lipid bilayer?

fatty acids

____ are small threadlike structures protruding from the cell surface used for locomotion.

flagellum

A cell in prophase I of meiosis has _____ as many copies of chromosomes as each of the daughter cells following cytokinesis of meiosis II.

four times

The first cells were surrounded by a membrane composed largely of lipids synthesized by intracellular proteins. As life on earth was starting, from what were the first membranes most likely formed?

lipids mixing in the watery environment

__________ provide cytoplasmic channels from one cell to an adjacent cell. They consist of special membrane proteins that surround a pore through which ions, sugars, amino acids, and other small molecules may pass. They are necessary for communication between cells in many types of tissues, including heart muscle and animal embryos.

gap junctions

The active maintenance of a constant internal environment is referred to as:

homeostasis

Which type of receptor is involved in rapid responses of muscle cells and neurons?

ligand-gated ion channel

Some transmembrane proteins are embedded in patches of plasma membrane with a specialized, non-random assortment of phospholipids, sphingolipids and cholesterol. These patches are referred to as:

lipid rafts

Which substance could most easily cross a synthetic membrane composed of phospholipids but not proteins?

oxygen (O2)

________ function like rivets, fastening cells together into strong sheets. Intermediate filaments made of sturdy keratin proteins anchor desmosomes in the cytoplasm.

loose junctions wrong desmosomes

Which proteins would be synthesized on the rough endoplasmic reticulum and processed in Golgi apparatus?

lysosomal enzymes that break down proteins in the lumen of the lysosome

Prokaryotic cells and eukaryotic cells reproduce by cell division. Regardless of the type of cell, all cells must _____ before they divide.

make a copy of their genetic information

Homologous pairs of chromosomes separate during:

meiosis I only

The various shades of human skin color are determined by the amount of _____.​

melanin in the skin

Which integumentary cell type is NOT matched with its correct characteristic?

melanocytes make calcium in the skin

The beaker in the illustration contains two solutions of salt with different concentrations (measured by molarity, M). The two solutions are separated by a membrane that is permeable to both salt and water. What will occur in this container?

net diffusion of water from A to B and of salt from B to A

RNA molecules are transported from the nucleus to the cytoplasm in eukaryotes through:

nuclear pores.

______ is the organelle in eukaryotic cells that holds the chromatin and ribosomal subunits.

nucleolus

______ is the semifluid medium inside the nucleus.

nucleoplasm

What type of secretion do sebaceous gland secrete?

oil through holocrine secretion

Some plant cells create a high concentration of protons outside the cell to move solutes, such as sucrose, across the plasma membrane into the cell where the sucrose concentration is already relatively high. This type of transport is an example of:

secondary active transport.

A cell membrane exhibits _______ which means it allows some substances to cross it more easily than others.

selective permeability

A cell membrane proteins exhibit _______ which means it acts to increase the rate of certain reactions by bringing specific substances closer together.

selective permeability wrong enzymatic activity

All of these events happen during M phase except:

synthesis of DNA

Which choice describes the hydrophilic component of cholesterol?

the hydroxyl head group

Which component is not considered part of the cytoplasm?

the nucleus

Which statement accurately describes a polar covalent bond?

the unequal sharing of electrons between an atom with a partial positive charge and an atom with a partial negative charge

Ion channels can be involved in cell signaling because:

they receive signals from other cells and lead to a cellular response.

Which level of burn may not be painful?​

third degree burn

At _________, the membranes of neighboring cells are very closely pressed against each other, bound together by specific proteins. Forming continuous seals around the cells, tight junctions prevent leakage of extracellular fluid across a layer of epithelial cells.

tight junctions

Nucleic acids are important information storage molecules present in virtually every cell. Which of the processes is carried out by a cell when it accesses that information in the DNA of the genes?

transcription and translation

An intact skin surface is the best way the body can defend itself against pathogens.​

true

Cells that have fully differentiated and no longer divide are said to be in G0 phase.

true

Observations are used by scientists to draw tentative explanations called hypotheses.

true

The medical prefix epi- means upon.​

true

The skin is designed to reduce the harmful effect of ultraviolet radiation contained in sunlight.​

true

There are three phases of interphase called: G1 phase, S phase and G2 phase.

true

There are two stages to the cell cycle: M phase and interphase.

true

The oxygen and hydrogens of a water molecule contains what type of bond?

van der Waals interactions wrong polar covalent

A patient who has burns on the entire left arm and entire left leg would have what percentage of body surface burned?​

​36 percent wrong ​27 percent