Chapter 4: Learnsmart

place the steps of transcription in order:

1. DNA is unwound and RNA polymerase attaches to the promoter of the gene 2. RNA polymerase forms an RNA copy of the gene 3. the RNA strand is released from the DNA strand

the sodium-potassium exchange pump transports __ sodium ions out of the cell for every __ potassium ions it transports into the cell

3, 2

during translation, the __ site is where the new amino acid joins the ribosome, the __ site is where the new polypeptide is forming and the __ site is from where the tRNA exits

A (aminoacyl) P (peptidyl) E (exit)

__ is not found in the plasma membrane

DNA

select all of the following that are required for transcription

DNA ribonucleotides RNA polymerase

rapid digestion of a cell by its own lysosomes is called __

autolysis

__ is the shape of a red blood cell

biconcave

types of transport proteins include __

carriers pumps channels

which statements describes the G2 phase of interphase

centriole production is completed it directly follows the S phase of interphase enzymes and other structures needed for cell division are syntehsized

the centrosome contains two __ that lie perpendicular to one another

centrioles

sodium ions move into the cell through __ -mediated diffusion

channel

match the DNA structures

chromatin: finely filamented mass of DNA and protein chromosomes: become visible only when the cell is dividing nucleosome: DNA double helix wound around a cluster of histones

which statements characterize metaphase?

chromosomes line up along the equatorial plate of the cell it directly follows prophase

which statements correctly describe the nuclear envelope?

continuous with the ER controls entry of substances into and out of the nucleus contains phospholipids double membrane

in the cell cycle, division of the cytoplasm is called __

cytokinesis

the study of cells is called __

cytology

the __ is a general term for all cellular contents between the plasma membrane and the nucleus

cytoplasm

the three components of the cytoplasm of a cell are __, __, and __

cytosol organelles inclusions

in cell division, one cell divides to produce two identical cells called __

daughter cells

when skin is pinched and twisted, __ keep the epidermal cells from ripping apart from one another

desmosomes

a transmission electron microscope (TEM) uses an __ to create an image for viewing

electron beam

__ is not a function of plasma membrane proteins

energy production

which of the following are classified as plasma membrane proteins?

enzymes receptor transport protein identity markers

true/false: loosely coiled DNA is referred to as a chromosome

false

true/false: the steeper the concentration gradient of a solute, the lower the osmotic pressure

false

true/false: in transcription a DNA gene is read and copied to produce a newly formed strand of DNA

false (in transcription a DNA gene is read and copied to produce a newly formed strand of RNA)

which are functions of rough ER?

formation of transport vesicles storage of proteins to be exported from the cell production of proteins

__ junctions allow small solutes to travel between adjacent cells

gap

body cells communicate to other immune cells that they both belong to the body and are healthy through direct contact that involves which part of the cell?

glycocalyx

the "coating of sugar" on the cell's surface is called the __

glycocalyx

select all that are found in the cell membrane

glycolipids cholesterol phospholipids

__ __ are an example of who might share the same pattern of sugars that extend from their cells in the form of a glycocalyx?

identical twins

match tonicity to its definition

isotonic: the cytosol and solution outside the cell have the same concentration of solutes. hypotonic: the solution outside the cell has a lower concentration of solutes than the cytosol. hypertonic: the solution outside the cell has a higher concentration of solutes than the cytosol.

which statements characterize telophase?

it directly follows anaphase it is the last phase of mitosis its processes are the reverse of prophase

the rate at which substances diffuse is not constant but is dependent upon which of the following?

magnitude of the concentration gradient temperature

the organelles that are the powerhouse of the cell because they perform aerobic respiration are __

mitochondria

__ is the cell division that takes place in somatic cells

mitosis

the nucleus is enclosed by a double membrane structure called the __

nuclear envelope

much of the internal content of the __ is the genetic material, DNA

nucleus

the organelle in which transcription takes place is the __

nucleus

a typical cell has how many nuclei?

one

during cell division, the centrosome functions to __

organize the microtubules that help move the chromosomes

the two major categories of membrane transport are __ transport that requires no energy expenditure and __ transport

passive active

osmosis is a type of __

passive transport

the bulk of the plasma membrane consists of a __

phospholipid bilayer

all materials that enter or leave the cell must pass across the __

plasma membrane

the __ forms the outer, limiting barrier separating the internal contents of the cell from the external environment

plasma membrane

match the event of mitosis with each phase

prophase: nucleolus disappears metaphase: microtubules from mitotic spindle attach to centromeres anaphase: centromeres that hold sister chromatid pairs separate telophase: chromosomes arrive at poles

when a protein is marked for destruction by having a protein called ubiquitin bound to it, the organelle responsible for this removal is __

proteasomes

__ is an active transport processes

receptor-mediated endocytosis

put the steps of translation into the proper order

ribosomal subunits bind the mRNA and a tRNA protein synthesis begins with the amino acid methionine anticodons and codons are paired; amino acids are joined a stop codon is read ribosomal subunits separate releasing the protein

which are required for translation?

ribosomes amino acids mRNA tRNA

match the non-membrane-bound organelles with their function:

ribosomes: synthesize proteins cytoskeleton: provides structural support within cells microfilaments: aid in muscle contraction and intracellular movements intermediate filaments: stabilize cell junctions

__ diffusion occurs when substances move across cell membranes unaided because they are either small, nonpolar, or both

simple

__ is a passive form of transport

simple diffusion

the synthesis of steroid hormones occurs in the __

smooth ER

__ cells include all of the cells in the body except sex cells

somatic

__ are common cell shapes

spherical column-like cube-like

which statements characterize prophase?

the nuclear envelope disappears it is the first stage of mitosis chromatin condenses into chromosomes

which of the following statements are true regarding integral proteins?

they act as identity markers for the cell they can act as receptors they can act as membrane channels

which statements are true regarding peripheral proteins?

they are attached loosely to the cell membrane they may serve as enzymes they can float and move about the phospholipid bilayer

which statements characterize microvilli?

they are smaller than cells they function to increase the surface area of the plasma membrane they are microscopic projections of the plasma membrane

which of the following statements correctly describe enzymes?

they may be attached to the internal or the external surface of a cell they are catalysts they are proteins

the three major type of membrane junctions are __ junctions, desmosomes, and gap junctions

tight

__ function like spot welds to seal off the intercellular space and prevent substances from passing between the cells

tight junctions

the process by which a DNA gene is copied into RNA is called __

transcription

the process in which a mRNA copy of a gene is read by ribosomes in the cytoplasm to produce a protein is called __

translation

the process that occurs on ribosomes by which a mRNA transcript is read and a new protein is produced is called __

translation

__ proteins provide a means of regulating movement of substances across the plasma membrane

transport

which are the functions of smooth ER?

transport of lipids synthesis of lipids metabolism of carbohydrates detoxification of alcohol

true/false: cilia and flagella are projections that extend from the surface of some cells

true

true/false: osmosis is a passive form of transport across the cell membrane

true