Chapter 3 - Cell Structures and Their Functions Flashcards
specialized structures called _________ perform specific functions
organelles
contains the cell’s genetic material
Nucleus
living material surrounding the nucleus; contains many types of organelles
Cytoplasm
encloses the cytoplasm
Cell membrane/plasma membrane
chemical reactions that occur within cells are called ____________.
cell metabolism
Energy released during metabolism is used for cell activities. True or False
True
the structural and functional characteristics of cells are determined by the type of atoms they produce. True or False
False - Molecules
cells produce and receive chemical and electrical signals that allow them to communicate with one another. True or False
True
specific cells transmit that genetic information to the next generation. True or False
specialized
Also known as the plasma membrane and is the outermost component of a cell
Cell membrane
substance outside the cell
Extracellular
substance inside the cell
Intracellular
Supports the cell contents, acts as a selective barrier that determines what moves into and out of the cell
Cell membrane
Plays a role in communication between cells
Cell membrane
Made up of two major types of molecules
Phospholipids and Proteins
Cell membrane also contains _______ and _________
cholesterol, carbohydrates
Phospholipids form a triple layer of molecules. True or False
False - Double
Polar, phosphate-containing ends of the phospholipids are _________
hydrophilic (water-loving)
Nonpolar, fatty acid ends of the phospholipids are _________
hydrophobic (water-fearing)
Face the extra- and intracellular fluids of the cell
hydrophilic (water-loving)
Face away from the fluid on either side of the membrane
hydrophobic (water-fearing)
Center of the double layer phospholipids
hydrophobic (water-fearing)
Phospholipids are not completely stationary but are able to move. True or False
True
Double layer of phospholipids has a liquid quality. True or False
False - fluid
Cholesterol within the phospholipid membrane gives it added strength and stability. True or False
True
Limiting the movement
Cholesterol
Protein among molecules
molecules “float” the phospholipid. True or False
True
Membrane protein function as membrane channels, carrier molecules, receptor molecules, enzymes or structural support in the membrane. True or False
True
involved with the movement of substances through the cell membrane
Membrane channels & carrier molecules
part of an intercellular communication system that enables cell recognition and coordination of the activities of cells
Receptor molecules
Cell membranes are ____________ where it allow some substance to pass into or out of the cells
selectively permeable
Enzymes, glycogen, potassium ion (K+) are found at ________ intracellularly
higher concentrations
Na+, Ca2+, and Cl- are found
in ______________ extracellularly
greater concentration
Nutrients enter cells _______
continually
Does not require the cell to expend energy
Passive membrane transport
Does require the cell to expend energy, usually in the form of ATP
Active membrane transport
Diffusion, osmosis, and facilitated diffusion
Passive membrane transport
Active transport, secondary active transport, endocytosis, exocytosis
Active membrane transport
substances dissolved in a predominant liquid or gas
Solute
predominant liquid or gas
Solvent
solutes, such as ions or molecules, tend to move from an area of higher concentration of a solute to an area of lower concentration of that same solute in solution – this process is called _______
diffusion
more solute particles occur in an area of higher concentration than in an area of lower concentration
diffusion
results from the natural, constant random motion of all solutes in a solution
diffusion
the difference in the concentration of a solute in a solvent between two points divided by the distance between the two points
concentration gradient
___________ when the concentration difference is large and/ or the distance is small
stepper
the substance moves down its concentration gradient, which means that the solute is diffusing from an area of higher concentration toward an area of lower concentration of that specific solute, vice versa. True or False
True
certain small, water-soluble substances can diffuse between the phospholipid molecules of cell membranes. True or False
True
other water-soluble substances, such as ions, can diffuse across the cell membrane freely. True or False
False - only by passing through cell membrane channels
molecules that are lipid-soluble, such as O2, CO2, and steroids, pass easily through the phospholipid bilayer. True or False
True
cell membrane channels vary in structure hence they vary in the degree to which ions pass through them. True or False
True
limit the movement of an ion across the membrane by opening and closing
Gated channels
allow ions to pass-through
Leak channels
_________ is important to cells because large volume changes caused by water movement can disrupt normal cell functions
Osmosis
Occurs when the cell membrane is less permeable, selectively permeable, or not permeable to solutes and a concentration gradient for water exists across the cell membrane
Osmosis
the force required to prevent the movement of water across a selectively permeable membrane
Osmotic pressure
As the solution rises, its weight produces __________, which moves water out of the tube back into the distilled water surrounding the tube
hydrostatic pressure
Measured by placing a solution into a tube that is closed at one end by a selectively permeable membrane and immersing the tube in distilled water
Osmotic pressure
Greater the concentration of a solution, greater its osmotic pressure, and greater the tendency for water. True or False
True
when an RBC is placed in a _________, water enters the cell by osmosis, causing the cell to swell or lyse
hypotonic solution
when an RBC is placed in a _________, water moves at the same rate, thus the cell shape remains normal
isotonic solution
when a RBC is places in a _________, water moves by osmosis out of the cell and into the solution, resulting in creation or cell shrinkage
hypertonic solution
Moves large, water-soluble molecules or electrically charged ions across the cell membrane
carrier-mediated transport mechanisms
Carrier-molecules are lipids within the cell membrane. True or False
False - proteins
a molecule to be transported binds to a specific carrier molecule on one side of the membrane. True or False
True
the binding of the molecule to the carrier molecule in the cell membrane causes the four-dimensional shape of the carrier molecule to change, and the transported molecule is moved to the opposite side of the cell membrane. True or False
False - three
carrier-mediated transport mechanisms exhibit specificity. True or False
True
protein involved in carrier-mediated transport is commonly identified by the specific substance transported. True or False
True
a carrier-mediated transport process that moves substances across the cell membrane from an area of higher concentration to an area of lower concentration of that substance
Facilitated diffusion
Facilitated diffusion requires energy in the form of ATP. True or False
False - metabolic energy in the form of ATP is not required
a carrier-mediated process that moves substances across the cell membrane from region of lower concentration to those of higher concentration against a concentration gradient
Active transport
if ATP is not available, active transport still continues with the use of lipids as their sour of energy. True or False
False - it stops
a genetic disorder that affects the active transport of Cl- into cells
Cystic Fibrosis
Involves the active transport of one substance across the cell membrane, establishing a concentration gradient
Secondary active transport
the diffusing substance moves in the same direction as the transported substance
Cotransport
the diffusing substance moves in a direction opposite to that of the transported substance
Countertransport
The diffusion of that transported substance down its concentration gradient provides the energy to transport a second substance across the cell membrane. True or False
True
Large water-soluble molecules that cannot be transported by carrier molecules, small pieces of matter, and even whole cells can be transported across cell membranes in membrane- bound sacs called ____________
vesicles
_________ is the uptake of material through the cell membrane by the formation of a vesicle
Endocytosis
When a specific substance binds to the receptor molecule, endocytosis is triggered, and the substance is transported into the cell
Receptor-mediated endocytosis
__________ is often used for endocytosis when solid particles are ingested
Phagocytosis
Endocytosis exhibits specificity. True or False
True
In some cells, membrane-bound sacs called _________ accumulate materials for release from the cells
secretory vesicles
secretory vesicles move to the cell membrane, where the vesicle membrane fuses with the cell membrane, and the material in the vesicle is released from the cell
Exocytosis
A large organelle usually located near the center of the cell
Nucleus
The nucleus is bounded by a ___________, consist of the outer and inner membrane with a narrow space between them
nuclear envelope
Inner and outer membranes come together to form __________, through which materials can pass into or out of the nucleus
nuclear pores
The nuclei of human cells contain 22 pairs of chromosomes, which consist of DNA and protein. True or False
True
During most of a cell’s life, chromosomes are loosely coiled and collectively called ___________
chromatin
diffuse bodies with no surrounding membrane that are found within the nucleus
Nucleoli
There are usually an abundant amount of nucleoli within the nucleus. True or False
False - There are usually one to several nucleoli within the nucleus
Subunits of ribosomes are formed within a nucleolus. True or False
True
Proteins produced in the cytoplasm move through the nuclear pores into the nucleus and to the nucleolus. True or False
True
Where proteins are produced
Ribosomes
Ribosomes that are not attached to any other organelle are called ________
free ribosomes
The _____________ is a series of membranes forming sacs and tubules that extend from the outer nuclear membrane into the cytoplasm
endoplasmic reticulum (ER)
ER with ribosomes attached to it
Rough ER
ER without ribosomes
Smooth ER
A site for lipid synthesis and participates in detoxification of chemicals within cells
Smooth ER
Large amount of rough ER in a cell indicates that it is synthesizing large amount of protein for export from the cell. True or False
True
Consists of closely packed stacks of curved, membrane- bound sacs
Golgi Apparatus
Collects, modifies, packages, and distributes protein and lipid manufactured by the ER
Golgi Apparatus
Golgi Apparatus is present in large numbers and is most highly developed in cells that secrete amino acids. True or False
False - proteins
small, membrane-bound sac that transports or stores materials within cells
Vesicle
In many cells, secretory vesicles accumulate in the cytoplasm and are released to the exterior when the cell receives a signal. True or False
True
Secretory vesicles containing hormones remain in the cytoplasm of endocrine cells until signals stimulate their release. True or False
True
membrane- bound vesicles formed from the Golgi Apparatus
Lysosomes
Pinch off from the Golgi Apparatus and move to the cell membrane
Vesicle
Enzymes within the
lysosomes break down the materials in the exocytotic vesicle. True or False
False - endocytotic
small membrane-bound vesicles containing enzymes that break down fatty acids, amino acids, and hydrogen peroxide (H202)
Peroxisomes
___________ is a by-product of fatty acid and amino acid breakdown and can be toxic to a cell
hydrogen peroxide
enzymes in peroxisomes break down hydrogen peroxide to water and O2. True or False
True
small organelles with inner and outer membranes separated by a space
mitochondria
outer membranes have a smooth contour, but the inner membranes have numerous folds called ________, which project into the interior of the mitochondria
cristae
material within the inner membrane of the mitochondria is the ________ and contains enzymes and mitochondrial DNA (mtDNA)
mitochondrial matrix
major sites of adenosine triphosphate (ATP) production within cells
mitochondria
Acts as the internal framework of the cell and consist of protein structures that support the cell, hold organelles in place, and enable the cell to change shape
cytoskeleton
hollow structures formed from protein subunits and perform variety of roles, includes helping to support the cytoplasm of cells, assisting in cell division, and forming essential components of certain organelles
Microtubules
small fibrils formed from protein subunits that structurally support the cytoplasm, determining cell shape and some are involved with cell movement
Microfilaments
fibrils formed from protein subunits that are smaller in diameter than microtubules but larger in diameter than microfilaments and provides mechanical support to the cell
Intermediate filaments
a protein associated with skin cells
Keratin
specialized area of cytoplasm close to the nucleus where microtubule formation occurs and contain two centrioles
Centrosome
small, cylindrical organelle composed of microtubules organized into nine triplets
Centriole
project from the surface of cells, vary in number from none to thousands per cell; capable of moving
CHOICES:
Cilia, Flagella, Microvilli
Cilia
have a structure similar to that of cilia but are much longer
CHOICES:
Cilia, Flagella, Microvilli
Flagella
Numerous on surface
cells that line respiratory tract
CHOICES:
Cilia, Flagella, Microvilli
Cilia
specialized extension of the cell membrane that are supported by microfilaments
CHOICES:
Cilia, Flagella, Microvilli
Microvilli
Sperm cells have ___________, which propels the sperm cell
CHOICES:
Cilia, Flagella, Microvilli
one flagellum
Transports mucus
CHOICES:
Cilia, Flagella, Microvilli
Cilia
Numerous on cells that have them and they increase the surface are of those cells
CHOICES:
Cilia, Flagella, Microvilli
Microvilli
Only one per cell
CHOICES:
Cilia, Flagella, Microvilli
Flagella
Do not actively move
CHOICES:
Cilia, Flagella, Microvilli
Microvilli
Cell’s characteristics are ultimately determined by the types of amino acid it produces. True or False
False - protein
DNA influences the structural and functional characteristics of the entire organism because it directs protein synthesis. True or False
True
sequence of nucleotides that provides a chemical set of instructions for making a specific protein
Gene
Nucleotide sequence of a gene determines the amino acid sequence of a specific protein. True or False
True
Copy of the gene produced during transcription is messenger RNA (mRNA) – travels from nucleus to the ribosomes in the cytoplasm, information in the copy is then used to construct a protein by means of translation
CHOICES:
Transcription, Translation
Transcription
Converting that copied information into a protein
CHOICES:
Transcription, Translation
Translation
Making a copy of a gene
CHOICES:
Transcription, Translation
Transcription
Occurs at ribosomes
CHOICES:
Transcription, Translation
Translation
DNA determines the structure of mRNA
CHOICES:
Transcription, Translation
Transcription
mRNA molecules produced by transcription pass through the nuclear pores to the ribosome
CHOICES:
Transcription, Translation
Translation
Ribosomes consist of small and large subunits, which combine with mRNA during translation
CHOICES:
Transcription, Translation
Translation
Information in mRNA is carried in groups of three nucleotides called _______
codons
Each tRNA there is a three-nucleotide sequence called the _______ that pairs with the codon of the mRNA
anticodon
An enzyme associated with the ribosome causes the formation of a _________ between the amino a
peptide bond
nondividing phase
Interphase
During ________, DNA (located in chromosomes in the cell’s nucleus) is replicated
interphase
DNA is dispersed throughout the nucleus as thin threads called ___________
chromatin
Human body
46 chromosomes
Sex cells formed in _________
meiosis
46 chromosomes are the haploid number of chromosomes and are organized to form 23 pairs of chromosomes. True or False
False - diploid
Parent cell divides to form two daughter cells with the same amount and type of DNA as parent cell
Mitosis
1 pair is the sex chromosomes and the remaining 22 pairs are called
autosomes. True False
True
chromatin condenses to form visible chromosomes
CHOICES:
Prophase, Metaphase, Anaphase, Telophase
Prophase
chromosomes align in the center of the cell in association with the spindle fibers
CHOICES:
Prophase, Metaphase, Anaphase, Telophase
Metaphase
Centrioles move to the opposite ends of the cell, and the nucleolus and the nuclear envelope disappear
CHOICES:
Prophase, Metaphase, Anaphase, Telophase
Prophase
Cytoplasm begins to divide
CHOICES:
Prophase, Metaphase, Anaphase, Telophase
Anaphase
Spindle fibers attach to the centromeres of each chromosome and begin moving them to the center of the cell
CHOICES:
Prophase, Metaphase, Anaphase, Telophase
Prophase
chromosomes disperse, the nuclear envelopes and the nucleoli form, and the cytoplasm continues to divide to form two cells
CHOICES:
Prophase, Metaphase, Anaphase, Telophase
Telophase
Chromosomes, assisted by the spindle fibers, move toward the centrioles at each end of the cell
CHOICES:
Prophase, Metaphase, Anaphase, Telophase
Anaphase
Process by which cells develop with specialized structures and function
Differentiation
Programmed cell death
Apoptosis
In developing fetus, apoptosis removes extra tissue. True or False
True
In some adult tissues, apoptosis eliminates excess
cell to maintain constant number of cells within the tissue. True or False
True
more sensitive to free-radical damage; result in loss of proteins critical to mitochondrial function
Mitochondrial damage
through time, DNA is damaged, resulting in cell degeneration and death
DNA damage
after a certain passage of time or certain number of cell divisions, results in the death of a given cell line
Cellular Clock
atoms or molecules with an unpaired electron
Free radicals
causing cells to deteriorate and die
CHOICES:
Death genes, Free radicals, Cellular Clock, DNA damage, Mitochondrial damage
Death genes
