Anatomy and Physiology Ch. 3 (Exam 1)

Why is it important that DNA replication take place before cell division? What would happen if cell division of a body cell took place without DNA replication, or when DNA replication was incomplete?

During cell division, one cell divides to produce two new cells. In order for all of the cells in your body to maintain a full genome, each cell must replicate its DNA before it divides so that a full genome can be allotted to each of its offspring cells. If DNA replication did not take place fully, or at all, the offspring cells would be missing some or all of the genome. This could be disastrous if a cell was missing genes necessary for its function and health.

Visit this link to see diffusion and how it is propelled by the kinetic energy of molecules in solution. How does temperature affect diffusion rate, and why? https://commons.wikimedia.org/wiki/File:Dispersion.gif

Higher temperatures speed up diffusion because molecules have more kinetic energy at higher temperatures.

A mutation in the gene for a cyclin protein might result in which of the following? a. a cell with additional genetic material than normal b. cancer c. a cell with less genetic material than normal d. any of the above

d. any of the above

hydrophilic

describes a substance or structure attracted to water

intracellular fluid (ICF)

fluid in the cytosol of cells

active transport

form of transport across the cell membrane that requires input of cellular energy

cell cycle

life cycle of a single cell, from its birth until its division into two new daughter cells

chromatin

substance consisting of DNA and associated proteins

ribosomal RNA (rRNA)

RNA that makes up the subunits of a ribosome

Why is receptor-mediated endocytosis said to be more selective than phagocytosis or pinocytosis?

Receptor-mediated endocytosis is more selective because the substances that are brought into the cell are the specific ligands that could bind to the receptors being endocytosed. Phagocytosis or pinocytosis, on the other hand, have no such receptor-ligand specificity, and bring in whatever materials happen to be close to the membrane when it is enveloped.

reactive oxygen species (ROS)

a group of extremely reactive peroxides and oxygen-containing radicals that may contribute to cellular damage

Place the following structures in order from least to most complex organization: chromatin, nucleosome, DNA, chromosome a. DNA, nucleosome, chromatin, chromosome b. nucleosome, DNA, chromosome, chromatin c. DNA, chromatin, nucleosome, chromosome d. nucleosome, chromatin, DNA, chromosome

a. DNA, nucleosome, chromatin, chromosome

What multipotent stem cells from children sometimes banked by parents? a. fetal stem cells b. embryonic stem cells c. cells from the umbilical cord and from baby teeth d. hematopoietic stem cells from red and white blood cells

c. cells from the umbilical cord and from baby teeth

Which type of stem cell gives rise to red and white blood cells? a. endothelial b. epithelial c. hematopoietic d. mesenchymal

c. hematopoietic

Which of the following structures could be found within the nucleolus? a. chromatin b. histones c. ribosomes d. nucleosomes

c. ribosomes

triplet

consecutive sequence of three nucleotides on a DNA molecule that, when transcribed into an mRNA codon, corresponds to a particular amino acid

anticodon

consecutive sequence of three nucleotides on a tRNA molecule that is complementary to a specific codon on an mRNA molecule

codon

consecutive sequence of three nucleotides on an mRNA molecule that corresponds to a specific amino acid

cleavage furrow

contractile ring that forms around a cell during cytokinesis that pinches the cell into two halves

pinocytosis

endocytosis of fluid

mitochondrion

one of the cellular organelles bound by a double lipid bilayer that function primarily in the production of cellular energy (ATP)

exon

one of the coding regions of an mRNA molecule that remain after splicing

transcription factor

one of the proteins that regulate the transcription of genes

cytoskeleton

"skeleton" of a cell; formed by rod-like proteins that support the cell's shape and provide, among other functions, locomotive abilities

sodium-potassium pump

(also, Na+/K+ ATP-ase) membrane-embedded protein pump that uses ATP to move Na+ out of a cell and K+ into the cell

gene expression

active interpretation of the information coded in a gene to produce a functional gene product

Which of the following sequences on a DNA molecule would be complementary to GCTTATAT? a. TAGGCGCG b. ATCCGCGC c. CGAATATA d. TGCCTCTC

c. CGAATATA

ligand

molecule that binds with specificity to a specific receptor molecule

splicing

the process of modifying a pre-mRNA transcript by removing certain, typically non-coding, regions

anaphase

third stage of mitosis (and meiosis), during which sister chromatids separate into two new nuclear regions of a dividing cell

intermediate filament

type of cytoskeletal filament made of keratin, characterized by an intermediate thickness, and playing a role in resisting cellular tension

nucleosome

unit of chromatin consisting of a DNA strand wrapped around histone proteins

somatic cell

all cells of the body excluding gamete cells

autolysis

breakdown of cells by their own enzymatic action

chromosome

condensed version of chromatin

sister chromatid

one of a pair of identical chromosomes, formed during DNA replication

organelle

any of several different types of membrane-enclosed specialized structures in the cell that perform specific functions for the cell

The rough ER has its name due to what associated structures? a. Golgi apparatus b. ribosomes c. lysosomes d. proteins

b. ribosomes

nucleus

cell's central organelle; contains the cell's DNA

phagocytosis

endocytosis of large particles

G1 phase

first phase of the cell cycle, after a new cell is born

Watch this video to learn about DNA replication. DNA replication proceeds simultaneously at several sites on the same molecule. What separates the base pair at the start of DNA replication? https://www.youtube.com/watch?v=FBmO_rmXxIw

an enzyme

How many "letters" of an RNA molecule, in sequence, does it take to provide the code for a single amino acid? a. 1 b. 2 c. 3 d. 4

c. 3

Which of the following is not a difference between DNA and RNA? a. DNA contains thymine whereas RNA contains uracil b. DNA contains deoxyribose and RNA contains ribose c. DNA contains alternating sugar-phosphate molecules whereas RNA does not contain sugars d. RNA is single stranded and DNA is double stranded

c. DNA contains alternating sugar-phosphate molecules whereas RNA does not contain sugars

Which of the following is a feature common to all three components of the cytoskeleton? a. They all serve to scaffold the organelles within the cell. b. They are all characterized by roughly the same diameter. c. They are all polymers of protein subunits. d. They all help the cell resist compression and tension.

c. They are all polymers of protein subunits.

Ion pumps and phagocytosis are both examples of ________. a. endocytosis b. passive transport c. active transport d. facilitated diffusion

c. active transport

glycocalyx

coating of sugar molecules that surrounds the cell membrane

spliceosome

complex of enzymes that serves to splice out the introns of a pre-mRNA transcript

diploid

condition marked by the presence of a double complement of genetic material (two sets of chromosomes, one set inherited from each of two parents)

The diffusion of substances within a solution tends to move those substances ________ their ________ gradient. a. up; electrical b. up; electrochemical c. down; pressure d. down; concentration

d. down; concentration

hydrophobic

describes a substance or structure repelled by water

pluripotent

describes the condition of being able to differentiate into a large variety of cell types

multipotent

describes the condition of being able to differentiate into different types of cells within a given cell lineage or small number of lineages, such as a red blood cell or white blood cell

unipotent

describes the condition of being committed to a single specialized cell type

receptor-mediated endocytosis

endocytosis of ligands attached to membrane-bound receptors

genome

entire complement of an organism's DNA; found within virtually every cell

interphase

entire life cycle of a cell, excluding mitosis

DNA polymerase

enzyme that functions in adding new nucleotides to a growing strand of DNA during DNA replication

helicase

enzyme that functions to separate the two DNA strands of a double helix during DNA replication

RNA polymerase

enzyme that unwinds DNA and then adds new nucleotides to a growing strand of RNA for the transcription phase of protein synthesis

exocytosis

export of a substance out of a cell by formation of a membrane-bound vesicle

histone

family of proteins that associate with DNA in the nucleus to form chromatin

selective permeability

feature of any barrier that allows certain substances to cross but excludes others

cytokinesis

final stage in cell division, where the cytoplasm divides to form two separate daughter cells

extracellular fluid (ECF)

fluid exterior to cells; includes the interstitial fluid, blood plasma, and fluid found in other reservoirs in the body

interstitial fluid (IF)

fluid in the small spaces between cells not contained within blood vessels

passive transport

form of transport across the cell membrane that does not require input of cellular energy

proteome

full complement of proteins produced by a cell (determined by the cell's specific gene expression)

gene

functional length of DNA that provides the genetic information necessary to build a protein

endocytosis

import of material into the cell by formation of a membrane-bound vesicle

cytoplasm

internal material between the cell membrane and nucleus of a cell, mainly consisting of a water-based fluid called cytosol, within which are all the other organelles and cellular solute and suspended materials

metaphase plate

linear alignment of sister chromatids in the center of the cell, which takes place during metaphase

autophagy

lysosomal breakdown of a cell's own components

cell membrane

membrane surrounding all animal cells, composed of a lipid bilayer interspersed with various molecules; also known as plasma membrane

nuclear envelope

membrane that surrounds the nucleus; consisting of a double lipid-bilayer

peripheral protein

membrane-associated protein that does not span the width of the lipid bilayer, but is attached peripherally to integral proteins, membrane lipids, or other components of the membrane

integral protein

membrane-associated protein that spans the entire width of the lipid bilayer

lysosome

membrane-bound cellular organelle originating from the Golgi apparatus and containing digestive enzymes

peroxisome

membrane-bound organelle that contains enzymes primarily responsible for detoxifying harmful substances

Which of the following is a function of the rough ER? a. production of proteins b. detoxification of certain substances c. synthesis of steroid hormones d. regulation of intracellular calcium concentration

a. production of proteins

flagellum

appendage on certain cells formed by microtubules and modified for movement

Which of the following phases is characterized by preparation for DNA synthesis? a. G0 b. G1 c. G2 d. S

b. G1

What is a primary function of tumor suppressor genes? a. stop all cells from dividing b. stop certain cells from dividing c. help oncogenes produce oncoproteins d. allow the cell to skip certain phases of the cell cycle

b. stop certain cells from dividing

stem cell

cell that is oligo-, multi-, or pleuripotent that has the ability to produce additional stem cells rather than becoming further specialized

ribosome

cellular organelle that functions in protein synthesis

promoter

region of DNA that signals transcription to begin at that site within the gene

kinetochore

region of a centromere where microtubules attach to a pair of sister chromatids

centromere

region of attachment for two sister chromatids

metaphase

second stage of mitosis (and meiosis), characterized by the linear alignment of sister chromatids in the center of the cell

polyribosome

simultaneous translation of a single mRNA transcript by multiple ribosomes

cilia

small appendage on certain cells formed by microtubules and modified for movement of materials across the cellular surface

nucleolus

small region of the nucleus that functions in ribosome synthesis

centriole

small, self-replicating organelle that provides the origin for microtubule growth and moves DNA during cell division

S phase

stage of the cell cycle during which DNA replication occurs

What are cyclins and cyclin-dependent kinases, and how do they interact?

A cyclin is one of the primary classes of cell cycle control molecules, while a cyclin-dependent kinase (is one of a group of molecules that work together with cyclins to determine progression past cell checkpoints. By interacting with many additional molecules, these triggers push the cell cycle forward unless prevented from doing so by "stop" signals, if for some reason the cell is not ready.

Discuss two reasons why the therapeutic use of embryonic stem cells can present a problem.

Embryonic stem cells derive from human embryos, which are destroyed to obtain the cells. The destruction of human embryos is an ethical problem. And, the DNA in an embryonic stem cell would differ from the DNA of the person being treated, which could result in immune problems or rejected of tissue.

Watch this video to learn about ribosomes. The ribosome binds to the mRNA molecule to start translation of its code into a protein. What happens to the small and large ribosomal subunits at the end of translation? https://www.youtube.com/watch?v=MiVqjxi0DfQ

They separate and move and are free to join translation of other segments of mRNA.

The nucleus and mitochondria share which of the following features? a. protein-lined membrane pores b. a double cell membrane c. the synthesis of ribosomes d. the production of cellular energy

b. a double cell membrane

Which of the following is part of the elongation step of DNA synthesis? a. pulling apart the two DNA strands b. attaching complementary nucleotides to the template strand c. untwisting the DNA helix d. none of the above

b. attaching complementary nucleotides to the template strand

Because they are embedded within the membrane, ion channels are examples of ________. a. receptor proteins b. integral proteins c. peripheral proteins d. glycoproteins

b. integral proteins

Choose the answer that best completes the following analogy: Diffusion is to ________ as endocytosis is to ________. a. filtration; phagocytosis b. osmosis; pinocytosis c. solutes; fluid d. gradient; chemical energy

b. osmosis; pinocytosis

Golgi apparatus

cellular organelle formed by a series of flattened, membrane-bound sacs that functions in protein modification, tagging, packaging, and transport

endoplasmic reticulum (ER)

cellular organelle that consists of interconnected membrane-bound tubules, which may or may not be associated with ribosomes (rough type or smooth type, respectively)

centrosome

cellular structure that organizes microtubules during cell division

polypeptide

chain of amino acids linked by peptide bonds

Arrange the following terms in order of increasing specialization: oligopotency, pleuripotency, unipotency, multipotency. a. multipotency, pleuripotency, oligopotency, unipotency b. pleuripotency, oligopotency, multipotenc, unipotency c. oligopotency, pleuripotency, unipotency, multipotency d. pleuripotency, multipotency, oligopotency, unipotency

d. pleuripotency, multipotency, oligopotency, unipotency

hypertonic

describes a solution concentration that is higher than a reference concentration

oligopotent

describes the condition of being more specialized than multipotency; the condition of being able to differentiate into one of a few possible cell types

homologous

describes two copies of the same chromosome (not identical), one inherited from each parent

telophase

final stage of mitosis (and meiosis), preceding cytokinesis, characterized by the formation of two new daughter nuclei

prophase

first stage of mitosis (and meiosis), characterized by breakdown of the nuclear envelope and condensing of the chromatin to form chromosomes

vesicle

membrane-bound structure that contains materials within or outside of the cell

transfer RNA (tRNA)

molecules of RNA that serve to bring amino acids to a growing polypeptide strand and properly place them into the sequence

diffusion

movement of a substance from an area of higher concentration to one of lower concentration

G0 phase

phase of the cell cycle, usually entered from the G1 phase; characterized by long or permanent periods where the cell does not move forward into the DNA synthesis phase

DNA replication

process of duplicating a molecule of DNA

Visit this link to learn about mitosis. Mitosis results in two identical diploid cells. What structures form during prophase? http://www.johnkyrk.com/mitosis.html

the spindle

Explain in your own words why DNA replication is said to be "semiconservative"?

DNA replication is said to be semiconservative because, after replication is complete, one of the two parent DNA strands makes up half of each new DNA molecule. The other half is a newly synthesized strand. Therefore, half ("semi") of each daughter DNA molecule is from the parent molecule and half is a new molecule.

What would happen if anaphase proceeded even though the sister chromatids were not properly attached to their respective microtubules and lined up at the metaphase plate?

One or both of the new daughter cells would accidently receive duplicate chromosomes and/or would be missing certain chromosomes.

Watch this video to learn about the endomembrane system, which includes the rough and smooth ER and the Golgi body as well as lysosomes and vesicles. What is the primary role of the endomembrane system? https://www.youtube.com/watch?v=UAaTEjYmxso

Processing, packaging, and moving materials manufactured by the cell.

mutation

change in the nucleotide sequence in a gene within a cell's DNA

cytosol

clear, semi-fluid medium of the cytoplasm, made up mostly of water

Which of the following is not made out of RNA? a. the carriers that shuffle amino acids to a growing polypeptide strand b. the ribosome c. the messenger molecule that provides the code for protein synthesis d. the intron

d. the intron

Choose the term that best completes the following analogy: Cytoplasm is to cytosol as a swimming pool containing chlorine and flotation toys is to ________. a. the walls of the pool b. the chlorine c. the flotation toys d. the water

d. the water

glycoprotein

protein that has one or more carbohydrates attached

microtubule

the thickest of the cytoskeletal filaments, composed of tubulin subunits that function in cellular movement and structural support

microfilament

the thinnest of the cytoskeletal filaments; composed of actin subunits that function in muscle contraction and cellular structural support

G2 phase

third phase of the cell cycle, after the DNA synthesis phase

Explain how a transcription factor ultimately determines whether or not a protein will be present in a given cell?

Transcription factors bind to DNA and either promote or inhibit the transcription of a gene. If they promote the transcription of a particular gene, then that gene will be transcribed and the mRNA subsequently translated into protein. If gene transcription is inhibited, then there will be no way of synthesizing the gene's corresponding protein.

Contrast transcription and translation. Name at least three differences between the two processes.

Transcription is really a "copy" process and translation is really an "interpretation" process, because transcription involves copying the DNA message into a very similar RNA message whereas translation involves converting the RNA message into the very different amino acid message. The two processes also differ in their location: transcription occurs in the nucleus and translation in the cytoplasm. The mechanisms by which the two processes are performed are also completely different: transcription utilizes polymerase enzymes to build mRNA whereas translation utilizes different kinds of RNA to build protein.

intron

non-coding regions of a pre-mRNA transcript that may be removed during splicing

What materials can easily diffuse through the lipid bilayer, and why?

Only materials that are relatively small and nonpolar can easily diffuse through the lipid bilayer. Large particles cannot fit in between the individual phospholipids that are packed together, and polar molecules are repelled by the hydrophobic/nonpolar lipids that line the inside of the bilayer.

Compare and contrast lysosomes with peroxisomes: name at least two similarities and one difference.

Peroxisomes and lysosomes are both cellular organelles bound by lipid bilayer membranes, and they both contain many enzymes. However, peroxisomes contain enzymes that detoxify substances by transferring hydrogen atoms and producing H2O2, whereas the enzymes in lysosomes function to break down and digest various unwanted materials.

Explain why the structure of the ER, mitochondria, and Golgi apparatus assist their respective functions.

The structure of the Golgi apparatus is suited to its function because it is a series of flattened membranous discs; substances are modified and packaged in sequential steps as they travel from one disc to the next. The structure of Golgi apparatus also involves a receiving face and a sending face, which organize cellular products as they enter and leave the Golgi apparatus. The ER and the mitochondria both have structural specializations that increase their surface area. In the mitochondria, the inner membrane is extensively folded, which increases surface area for ATP production. Likewise, the ER is elaborately wound throughout the cell, increasing its surface area for functions like lipid synthesis, Ca++ storage, and protein synthesis.

What do osmosis, diffusion, filtration, and the movement of ions away from like charge all have in common? In what way do they differ?

These four phenomena are similar in the sense that they describe the movement of substances down a particular type of gradient. Osmosis and diffusion involve the movement of water and other substances down their concentration gradients, respectively. Filtration describes the movement of particles down a pressure gradient, and the movement of ions away from like charge describes their movement down their electrical gradient.

Briefly explain the similarities between transcription and DNA replication.

Transcription and DNA replication both involve the synthesis of nucleic acids. These processes share many common features—particularly, the similar processes of initiation, elongation, and termination. In both cases the DNA molecule must be untwisted and separated, and the coding (i.e., sense) strand will be used as a template. Also, polymerases serve to add nucleotides to the growing DNA or mRNA strand. Both processes are signaled to terminate when completed.

Which of the following organelles produces large quantities of ATP when both glucose and oxygen are available to the cell? a. mitochondria b. peroxisomes c. lysosomes d. ER

a. mitochondria

Transcription and translation take place in the ________ and ________, respectively. a. nucleus; cytoplasm b. nucleolus; nucleus c. nucleolus; cytoplasm d. cytoplasm; nucleus

a. nucleus; cytoplasm

amphipathic

describes a molecule that exhibits a difference in polarity between its two ends, resulting in a difference in water solubility

hypotonic

describes a solution concentration that is lower than a reference concentration

isotonic

describes a solution concentration that is the same as a reference concentration

concentration gradient

difference in the concentration of a substance between two regions

electrical gradient

difference in the electrical charge (potential) between two regions

facilitated diffusion

diffusion of a substance with the aid of a membrane protein

osmosis

diffusion of water molecules down their concentration gradient across a selectively permeable membrane

mitosis

division of genetic material, during which the cell nucleus breaks down and two new, fully functional, nuclei are formed

totipotent

embryonic cells that have the ability to differentiate into any type of cell and organ in the body

channel protein

membrane-spanning protein that has an inner pore which allows the passage of one or more substances

mitotic spindle

network of microtubules, originating from centrioles, that arranges and pulls apart chromosomes during mitosis

messenger RNA (mRNA)

nucleotide molecule that serves as an intermediate in the genetic code between DNA and protein

cyclin-dependent kinase (CDK)

one of a group of enzymes associated with cyclins that help them perform their functions

cyclin

one of a group of proteins that function in the progression of the cell cycle

nuclear pore

one of the small, protein-lined openings found scattered throughout the nuclear envelope

mitotic phase

phase of the cell cycle in which a cell undergoes mitosis

translation

process of producing a protein from the nucleotide sequence code of an mRNA transcript

transcription

process of producing an mRNA molecule that is complementary to a particular gene of DNA

checkpoint

progress point in the cell cycle during which certain conditions must be met in order for the cell to proceed to a subsequence phase

receptor

protein molecule that contains a binding site for another specific molecule (called a ligand)