Cellular Biology Flashcards
This structure generate ATP by oxidative phosphorylation; it is a ___________
Mitochondrion
This structure synthesizes proteins; it is a
Ribosome
This structure processes and packages proteins for delivery; it is the
Golgi apparatus
This structure serves as a repository of genetic information; it is the
Nucleus
This structure synthesizes steroid hormones and folds proteins; it is the
Endoplasmic Reticulum
This structure synthesizes ribosomes; it is the
nucleolus
this structures delivers proteins that are secreted to their destination; it is a secretory
vesicule
this structure contains digestive enzymes; it is a
lysosome
what is the difference between a eukaryote and a prokaryote?
A eukaryote has numerous organelles and a membrane surrounding is nucleus, but a prokaryote does not have organelles, and its genetic material is not organized into a nucleus.
What is the diffenece between the nucleolus and the nucleus?
The nucleolus is a small, dense structure within the nucleus.
What is the difference between hydrophilic and hydrophobic?
A hydrophilic substance attracts water, but a hydrophobic substance repels water
What is the difference between microtubules and microfilaments?
Microtubules are tiny, somewhat rigid, single unbranched protein tubes, but microfilaments are smaller, more flexible fibrils of actin that usually occur in bundles. both are part of the cytoskeleton.
What is the difference between a lysosome and a peroxisome?
Lysosomes and peroxisomes contain different enzymes. Lysosomes contain digestive enzymes that break down molecules to their component parts, whereas peroxisomes contain oxidative enzymes that are important in producing hydrogen peroxide and other reactive oxygen species.
Protein in the nucleus that bind DNA and help regulate its activity are called ___________?
histones
Cells such as neutrophils that use hydrogen peroxide as a defensive weapon synthesize it in their _______.
perozisones
A section of a membrane that is rich in cholesterol and helps organize membrane proteins is called a lipid ______.
raft
The cells that secrete the extracellular matrix are called __________.
fibroblasts
The mechanical force of water pushing against cellular membranes is called ___________ pressure.
hydrostatic
An _______ solution has the same osmolality as normal body fluids.
isotonic
In a simple epithelium, the epithelial cells are in contact with a __________ membrane that provides support.
Basement
__________ tissue is characterized by only a few cells surrounded by a lot of extracellular matrix.
connective
A myocyte is a ____________ cell.
muscle
put the letters in the correct order of events that occur during a neuronal action potential:
A: Sodium ions move into the cell.
B: Potassium ions leave the cell.
C: Sodium permeability increases.
D: Resting membrane potential is reestablished.
E: Potassium permeability increases.
C,A,E,B,D
Put the letter in orders in the phases of the normal cell cycle, beginning with the phase that precedes DNA synthesis.
A: M phase
B: S phase
C: G1 Phase
D: G2 Phase
C,B,D,A
The difference between cells that divide rapidly and those that divide slowly is the amount of time they spend in the _____ phase of the cell cycle.
A: s phase
B: G1 phase
B: G1 phase
Cells develop specialized functions through the process of __________.
A: differentiation
B: intermediary
C: metabolism
A: Differentiation
A particle that is dissolved is called _______.
A: substrate
B: Solute
B: solute
Mitochondria need a lot of ____________ to function normally.
A: glucose
B: oxygen
B: oxygen
During osmosis, ______________ move across the plasma membrane.
A: particles
B: water molecules
B: water molecules
______________ signals act on nearby cells by __________ through interstitial fluid.
A:Autocrine
B: Paracrine
C: diffusion
D: active transport
A: Paracrine; C: diffusion
A cell that has an insufficient oxygen supply will not be able to perform the chemistry of ________.
A: the Krebs cycle
B: glycolysis
A: the Krebs cycle
__________ can move substances against their concentration gradients.
A: Active transport
B: Facilitated diffusion
Active transport
Receptors are _________________ that bind specific small molecules.
A: proteins
B: lipids
proteins
ER stress occurs when unfolded or misfolded _______ accumulate in the endoplasmic reticulum.
A: lipids
B: proteins
proteins
What is the definition of Ligand?
A substance that binds to a receptor
What is the definition of Caveolae?
Tiny flask-shaped pits in the outer surface of the plasma membrane may be essential locations for receptors or for entry of molecules into the cell.
What is the definition of Mechanotransduction?
Translating mechanical stimuli into biochemical signals.
What is the definition of Amphipathic molecule?
A molecule that has both a hydrophobic part and a hydrophilic part
What is the definition of Endocytosis?
Infolding of the plasma membrane to form a vesicle that enters the cell.
If the ECF becomes hypotonic, in which direction will water move?
A: from ECF into the cell
B: From the cell to ECF
A: from ECF into the cell
If the concentration of substance X in the ECF is higher than its concentration inside the cell, in which direction will active transport move substance X?
A: from ECF into the cell
B: From the cell to ECF
B: from the cell to ECF
If the glucose concentration in the ECF is higher than its concentration inside the cell, in which direction will facilitate diffusion move glucose?
A: from ECF into the cell
B: From the cell to ECF
A: from ECF into the cell
In which direction does Na1, K1-ATPase move sodium ions?
A: from ECF into the cell
B: From the cell to ECF
B: From the cell to ECF
in which direction does NA+, K+ATPase move potassium ions?
A: from ECF into the cell
B: From the cell to ECF
A: from ECF into the cell
A mutation affecting what function would cause a lysosomal storage disease?
Lysosomal enzymes normally digest nutrients debris and other items that should be removed from the cell. A mutation that causes dysfunction or lack of a lysosomal enzyme will allow items that cannot be digested to accumulate inside lysosomes creating a lysosomal storage disease.
How does the presence of gap junctions in cardiac muscle facilitate cardiac function?
Gap junction synchronize contractions of heart muscle cells through ionic coupling.
Explain why intracellular receptors do not use second messages, but many cell surface receptors do.
Cell surface receptors use second messengers because the ligand (the first messenger) cannot enter the cell. Intracellular receptors do not need a second messenger because the ligand enters the cell.
What happens during the interphase portion of the cell cycle? Why are those events important?
During interphase (the G1, S, and G2 phases), the cell increases its mass by producing DNA, RNA, protein, lipids, and other substances, and duplicates its chromosomes. These processes are necessary to prepare the cell for mitosis and cytokinesis.
It is true that a eukaryotic cell:
A: it is smaller than a prokaryotic cell.
B: contains structures called organelles.
C: lacks a well-defined nucleus.
D: does not contain histones.
B: Eukaryotic cells contain organelles and histones, they have a well-defined nucleus, and are larger than prokaryotic cells
The function of a histone found in a eukaryote cell focuses on cellular:
A: division.
B: movement.
C: activities.
D: deoxyribonucleic acid (DNA) folding.
D: The histones are binding proteins that cause the supercoiling of DNA into chromosomes and do not affect cellular division, movement, or activities.
An organelle that is responsible for the metabolism of cellular energy is referred to as a/an:
A: Golgi complex.
B: mitochondrion
C: endoplasmic reticulum.
D: nucleolus.
B: Mitochondria play a role in cellular metabolism, cellular respiration, and energy production. The Golgi complex is responsible for processing and packaging proteins from the endoplasmic reticulum, where they are synthesized. The nucleolus is a small, dense structure that contains ribonucleic acid (RNA), DNA, and DNA-binding proteins.
Which statement best describes a desmosome?
A: desmosome is a barrier to diffusion.
B: Desmosomes hold cells together by continuous bands.
C: A desmosome is a communicating tunnel.
D: Desmosomes function as a zona occludens
B: The desmosome is a type of cell junction. The other two types include tight junctions and gap junctions. Desmosomes hold cells together by forming a continuous band of epithelial tissue or belt (or button-like) points of contact. They are also a source of structural stability. Tight junctions serve as barriers to diffusion and prevent the movement of substances through transport proteins. Gap junctions are clusters of communicating tunnels
Which statement describes the function of a second messenger?
A: Binds with membrane-bound receptors via a ligand
B: Triggers a cascade of intracellular events
C: Opens specific channels in the cell membrane
D: Blocks a membrane-bound receptor signal
C: The binding of a ligand to a cell surface receptor triggers the activation of intracellular second messengers. Second messengers activate signal transduction pathways in the cell that can initiate different intracellular events. Cyclic adenosine monophosphate (cAMP) and calcium (Ca++) are the two major second-messenger pathways. The first messengers are the extracellular ligands that bind to cell surface receptors. The binding of first messengers can result in an opening or closing of specific cell membrane channels or activating second messengers.
Which statement is correct regarding cellular energy?
A: Glycolysis is the building of sugar molecules.
B: Oxidative cellular metabolism is a single reaction making adenosine triphosphate (ATP).
C: Oxidative phosphorylation occurs in the mitochondria.
D: Anaerobic glycolysis occurs in the presence of oxygen
C: Oxidative phosphorylation occurs in the mitochondria. This is the mechanism by which the energy produced from carbohydrates, fats, and proteins is transferred to ATP. Glycolysis is a process that breaks down glucose molecules; it produces a net of two ATP molecules. Oxidation is a process during which a pair of electrons are removed and transferred. Oxidative cellular metabolism involves 10 biochemical reactions.
The movement of a solute molecule from an area of high concentration to an area of low concentration is called:
A: diffusion.
B: filtration.
C: osmosis.
D: hydrostatic pressure.
A: Diffusion is the movement of a solute from an area of high concentration to an area of low concentration. Osmosis is the movement of water down a concentration gradient from an area of higher water concentration to an area of lower water concentration. Filtration is the movement of water and solute through a membrane because of greater pushing pressure on one side of the membrane than the other. Hydrostatic pressure is the mechanical force of water pushing against a cell membrane.
Which is an example of an energy-releasing process?
A: Anabolism
B: Catabolism
C: Substrate-induced reaction
D: Second messenger system
B: Catabolism is an energy-releasing process. The energy-using process is anabolism. A substrate is a specific substance that is converted to a product in the reaction. A second messenger is a “pass-it-on signal.” This occurs when a first messenger activates a receptor that then triggers a pass-it-on signal.
Which describes an amphipathic molecule?
A: It is permeable to water only.
B: It is a nonpolar molecule.
C: It is both hydrophobic and hydrophilic.
D: It is a one-layered structure.
C: The amphipathic molecule is both hydrophobic and hydrophilic. A hydrophilic molecule is a charged, water-loving molecule. A hydrophobic molecule is an uncharged or water-hating molecule. A polar molecule is another name for an amphipathic molecule.
Which are the roles of relay chains in signal transduction? (Select all that apply.)
A: Transfer the signal
B: Converge the signal
C: Amplify the signal
D: Distribute the signal
A, C, D
The functions of relay chains include transferring the signal from its reception point to another part of the cell where it is expected; amplifying the signal received and making it stronger; and distributing the signal so that it influences several processes in parallel. The signal can diverge, not converge, and be relayed to several different intracellular targets.
Which are the functions of a protein? (Select all that apply.)
A: Pores or transport channels
B: Enzymes that drive pumps
C: Cell surface markers
D: Synapses for cells
A, B, C.
Proteins may act as transport channels, pores, cell surface markers, enzymes that drive pumps, catalysts, and cell adhesion molecules (CAMs), or they may act as the key components of ATP synthesis. Synapses are the connections between two nerve cells.
Cells become specialized through what processes?
Differentiation or maturation
What are the eight specialized cellular functions of the cell?
- movement
- conductivity
- metabolic absorption
- secretion
- excretion
- respiration
- reproduction
- communication
the eukaryotic cell consists of three general components
the plasma membrane
the cytoplasm and the intracellular organelles
What is the largest organelle in the cell?
the nucleus and it is found in the cell’s center
what is the chief function of the Nucleus?
the nucleus is in charge of cell division an genetic information
what is the cytoplasm?
the cytoplasm or cytoplasmic matrix is an aqueous solution that fills the space between the nucleus and the plasma membrane
What is the Endoplasmic reticulum?
The endoplasmic reticulum or ER is a network of tubular channels(cisternae) that extends throughout the outer nuclear membrane.
What does the ER specialize in doing in the cell?
The ER synthesis and transports proteins and lipid components of most of the organelles. Its most important function is protein folding and sensing cell stress.
What is the Golgi complex?
The Golgi complex is a network of smooth membranes and vesicles located near the nucleus.
What does the Golgi complex do in the cell?
The Golgi complex is responsible for processing and packaging proteins into secretory vesicles that break away from the Golgi complex and migrate to a variety of intracellular and extracellular destinations, including the plasma membrane.
What are lysosomes?
Lysosomes are sac-like structures that originate from the Golgi complex and contain digestive enzymes. these enzymes are responsible for digesting most cellular substances to their basic components, such as amino acids, fatty acids, and carbohydrates.
What is another new role that Lysosomes play in the cell?
a newly understood role is nutrient-dependent signal transduction. the signaling function cooperates with the known degradative role to mediate basic cell functions, such as nutrient sensing, metabolic adaptation, and quality control of proteins and organelles.
What are the four pathways of degradation in lysosomes?
endocytosis, phagocytosis, macropinocytosis, autophagy
what are peroxisomes?
Peroxisomes are similar to lysosomes but they contain several oxidative enzymes such are catalase and urate oxidase.
What is the role of the mitochondria in the cell?
the mitochondria are found in great numbers in most cells and are responsible for cellular respiration and energy production.
What are the functions of the cytoplasm?
Intermediary metabolism involving enzymatic biochemical reactions; ribosomal protein synthesis; and storage of carbohydrate, fat and secretory vesicles.
The plasma membrane is a bilayer of lipids and proteins and has what functions?
The functions include recongition and binding units for substances moving in and out of the cell; pores or transport channels; enzymes that drive active pumps; dell surface markers such as glycoproteins; cell adhesion molecules; and catalysts of chemical reactions.
Cells are held together by three different means.
a the extracellular membrane
b cell adhesion molecules in the cell’s plasma membrane
c specialized cell junctions
The extracellular matrix includes three types of protein fibers
Collage, elastin and fobronectin. the matrix helps regulate cell growth and differentiation
Describe the basal lamina
the basal lamina is a basement membrane or a thin layer of connective issue underlying the epithelium of many organs.
What are Cell adhesion molecules or CAMs?
Cell adhesion molecules are cell surface proteins that bind to an adjacent cell and to components of the extracellular matrix.
What are the four main protein families that makeup CAMs?
the integrins, the cadherins, the selectins, and the immunoglobulin (Ig) superfamily
What are the three main types of cell junctions?
Desmosomes, tight junctions and gap junctions
What are the three main ways of cell communication?
- plasma membrane-bound signaling molecules affect the cell and other cells in direct physical contact.
- they activate receptor proteins inside the target cell, and the signal molecule has to enter the cell to bind to them
- they form protein channels (gap junctions) that directly coordinate the activities
What are the primary modes of intercellular signaling?
contact-dependent, paracrine, hormonal, neurohormonal and neurotransmitter
Prevents water soluble molecules from entering cells across the plasma membrane
Phospholipid bilayer
Hydrophobic
uncharged; water fearing
Hydrophillic
charged; water loving
Plasma membrane
Impermeable to most water-soluble molecules, but allows lipid-soluble molecules (o2/Co2) and uncharged particles such as H2o, Co2, and urea to diffuse it readily
Passive transport
no-energy transport of uncharged molecules through any semi-permeable barrier; ex. H2o and Co2 diffusing readily across plasma membrane
Diffusion
Movement of a solute molecule from an area of greater solute concentration to an area of lesser solute concentration
Filtration
Movement of H2o and solute through a membrane b/c of a greater pushing pressure on one side of the membrane
Osmosis
Movement of H2o down a concentration gradient, across a semi-permible membrane from a regions of higher concentration to lower concentration
Active Transport
The protein transporter moves molecules against, or up, the concentration gradient. Requires the expenditure of ATP and bigger molecules suchs a protein, ions, large cells, and complex sugars
Endocytosis
A section of the plasma membrane enfolds substances from outside the cell, invaginates (folds inward), and separates from the plasma membrane, forming a vesicle that moves into the cell.
Pinocytosis
Cell drinking; involves the ingestion of fluids and solute molecules through formation of small vesicles
Phagocytosis
Cell eating; involves the ingestion of large particles, such as bacteria, through formation of large molecules
Exocytosis
Secretion of macromolecules; helps replace portions of the plasma membrane; also releases molecules synthesized by the cells into the ECF
Endocrine Signaling
A form of cellular communication; remote signaling by secreted molecules (hormones) in the blood to remote cells
Paracrine Signaling
A form of cellular communication; secretion of local chemical mediators that are quickly taken up and immobilized. Contact signaling by plasma membrane molecules.
Synaptic Signaling
A form of cellular communication; secretion of neurotransmitters at specialized junctions call the chemical synapse. Contact signaling via specialized junctions.
Glycolysis
The second phase of cellular energy production, following digestion. A glucose molecule is split and two ATP molecules are formed through oxidation
Oxidative Phosphorylation
Occurs in the mitochondria; process by which energy is transferred into ATP
Mitosis
The reproduction of somatic cells; nuclear division followed by cytokinesis (cytoplasmic division); asexual
The result of mitosis
2 genetically identical daughter cells from 1 parent
Two important second-messager pathways are?
cAMP and Ca++
what is G protein used for in the cell?
G protein is and intermediary between the receptor and adenylyl cyclase
Anabolism is what?
Anabolism is the energy using process of metabolism
Catabolism is what?
Catabolism is the energy releasing process of metabolism
what is ATP
ATP functions as an energy-transferring molecule. Energy is stored by molecules of carbohydrates, lipids, and protein which when catabolized transfer energy to ATP.
Osmotic pressure
The amount of hydrostatic pressure required to oppose the osmotic movement of water is called osmotic pressure of the solution
Exocytosis
Exocytosis is the discharge of secretion of material from the intracellular vesicles at the cell surface. there is two main functions. replacement of portions of the plasma membrane that have been removed by endocytosis and release of molecules synthesized by the cells into the extracellular matrix.
Pinocyctosis
this is a type of endocytosis in the fluids and solute molecules are ingested through formation of small vesicles
