BSC 114 Exam 2

What are the components of the cell theory

-All living things are composed of one or more cells -Cells are the basic units of structure and function in living things (the cell is the simplest collection of matter capable of preforming all the activities of life) -Every cell originates from another cell; therefore, all cells are related by their descent from earlier cells

Characteristics of prokaryotic cells

-No membrane bound organelles -DNA. contained in the nucleoid. Usually circular in structure -Cytoplasm

What can lysosomal enzymes do?

-hydrolyze proteins, lipids, polysaccharides, or nucleic acids. -the breakdown products are used to synthesize new macromolecules -Can fuse with food vacuoles and hydrolyze/digest/break down their contents

Confocal Microscopy

-lasers and special optics are used to image specimen within a very narrow focal plane -images are acquired point-by-point and reconstructed with a computer -most often used with fluorescently stained specimens

What are some functions of microtubules

-maintenance of cell shape (compression resistance) -cell motility -chromosome movements in cell division -organelle movements

What are some functions of microfilaments?

-maintenance of cell shape (tension bearing elements) -changes in cell shape -muscle contraction -cytoplasmic streaming -cell motility (pseudopodia) -cell division (cleavage furrow formation)

What are some functions of intermediate filaments?

-maintenance of cell shape (tension-bearing elements) -anchorage of nucleus and certain other organelles -formation of nuclear lamina -found only in animal cells

Functions of the cytoskeleton

-organizes the cell's structures and activities -provides mechanical support for cells needed to maintain and alter cell shape -anchors organelles in eukaryotic cells -enables cellular motion (via flagella,cilia, and lamellipodia) -plays important roles in intracellular transport and cell division

Major functions of membrane proteins

-transport -enzymatic activity -signal transduction -cell-cell recognition -intercellular joining -attachement to cytoskeleton and extracellular matrix

glycolysis of a single glucose molecule leads to ___ turns of the citric acid cycle

2. pyruvate needed for each

What is the core of microtubules (like cilia and flagella)?

9 doublets arranged in a ring with a pair of microtubules in the center, sheathed by the plasma membrane

Bound ribosomes

Attached to the endoplasmic reticulum; make proteins that will be parts of cell membranes, packaged inside other organelles, or exported

Some functions of peroxisomes

Break down of fats into smaller molecules in the liver, detoxify alcohol and other harmful compounds by transferring hydrogen from the poisons to oxygen

What are the different types of Light Microscopy?

Bright field microscopy Phase-contrast microscopy Differential Interference Contrast microscopy Fluorescence Microscopy Confocal Microscopy

Electron Microscopy

Can visualize surface or intracellular features of a specimen

Plants use these to store organic compounds, inorganic ions, pigments, and poisonous substances

Central Vacuoles

Sites of photosynthesis in plants and algae

Cholorplasts

Side of the golgi apparatus that receives vesicles from the ER

Cis face

Cisternal maturation

Cisternal maturation is the process by which the cisternae of the Golgi apparatus progress from the cis face to the trans face

What are used by many fresh water protists to pump excess water out of the cell?

Contractile vacuoles

Rough ER

Cytoplasmic surface studded with ribosomes

What is the aqueous semifluid bounded by the plasmamembrane

Cytosol

Characteristics of eukaryotic cells

DNA- Usually linear in structure. contained in nucleus Membrane-bound organelles Cytoplasm Larger then prokaryotic cells

What kind of membrane does the nuclear envelope have?

Double membrane (2 phospholipid bilayers)

What completes the final steps in the processing of membrane, organelle-targeted, and secreted proteins

ER lumen

What is the purpose of cell fractionation

Enables scientists to determine the functions of organelles using biochemistry techniques that correlate cell function with structure

Made of glycoproteins and other macromolecules.

Extracellular matrix

What are the different types of vacuoles?

Food Contractile Central fungal

Mitochondrial Diseases

Friedrich's disease Leber's hereditary optic neuropathy Leigh disease Parkinson's disease Alzheimer's disease Maternally inhierted diabetes and deafness

Have hydrolytic functions (breakdown) comparable to those lysosomes in animal cells

Fungal Vacuoles

Modifies products of ER Manufactures certain macromolecules, such as secreted polysaccharides Sorts and packages materials into transport vesicles that can be targeted to the plasma membrane (for localization or secretion) and other organelles

Golgi Apparatus- protein products are modified while traveling inside the golgi from the receiving end to the shipping end

The _____ serves as the finishing and shipping area for products of the endomembrane system. This organelle adds molecular identification tags, or shipping codes, to products bound for other parts of the cell.

Golgi apparatus

___ is highly reactive and toxic to cells. Yet, it is contained within the peroxisomes

H2O2

Tay-Sachs is caused by the mutation in what gene?

HEXA gene. encodes an enzyme called hexosaminidase A

How many mitochondria can by in a cell?

Hundreds or thousands depending on its metabolic activity

Where do lysosomal enzymes work best?

In the acidic environment inside the lysosome

What is the most common form of TSD?

Infantile TSD. the nerve cells become distended with gangliosides and a deterioration of mental and physical abilities occurs -become blind, deaf, and unable to swallow - Death usually around age 4 or 5

What are some peroxisomal disorders?

Infantile refsum disease neonatal adrenoleukodystrohpy Rhizomelic chondrodysplasia punctata type 1 zellweger syndrome

The nuclear lamina is composed of:

Intermediate filaments and membrane-associated proteins

What is lysosome lumen?

It is the space bounded by the lysosome membrane

Smooth ER

Lacks ribosomes on cytoplasmic surface

Cristae provides a ___ surface are for enzymes involved in the synthesis of __

Large; ATP

What functions are completed by the smooth ER

Lipid synthesis Calcium ion storage Poison detoxification

Which organelle plays a role in intracellular digestion? ANSWER: plasmodesma ribosome Golgi apparatus chloroplast lysosome

Lysosome

A membranous sac of hydrolytic enzymes that can break down macromolecules and organelles that are damaged or no longer needed

Lysosomes

What processes are completed in Lysosomes

Macromolecule digestion Autophagy

What factors affect a microscopes ability to resolve cellular features?

Magnification Resolution Contrast

What are the 3 main types of protein fibers that make up the cytoskeleton in most eukaryotic cells?

Microtubules Microfilaments (actin filaments) Intermediate filaments

Site of cellular respiration

Mitochondria

Transport other proteins, vesicles, and organelles within the cell along cytoskeletal fibers. powered by ATP

Motor proteins

Do larger organisms have larger cells?

No. They have more cells. If cells were bigger they would not receive adequate nutrients and waste would build up

What maintains the shape of the nucleus?

Nuclear lamina

What regulates the entry and exit of many molecules from the nucleus

Nuclear pores

Autosomal Recessive developmental disorders that also result in skeletal and craniofacial dysmorphism, liver dysfunction, progressive sensorineural hearing loss, and retinopathy

Peroxisomal Disorders

Contain enzymes that transfer hydrogen from various substances to oxygen, producing hydrogenperoxide

Peroxisomes

Involved in the break down of long-chain fatty acids and other metabolic processes via oxidative reactions

Peroxisomes

The selective barrier that allows sufficient passage of oxygen, nutrients, and waste to service the volume of the cell

Plasma membrane

What is the name for the phospholipid bilayer that is embedded with many proteins and surrounds the cell?

Plasma membrane

What are the basic features of all cells?

Plasma membrane Cytosol Chromosomes (DNA) Ribosomes

What is autophagy?

Process by which lysosomes use enzymes to recycle the cell's own organelles and macromolecules

What processes are completed in the Rough ER

Protein Synthesis

What processes are completed in the Golgi Apparatus

Protein modification Cisternal Maturation

Large numbers of ribosomes are present in cells that specialize in producing which of the following molecules? ANSWER: starches steroids proteins glucose lipids

Proteins

What are the very large protein- RNA complexes that carry out protein synthesis (translation)

Ribosomes

What part of the cell carries out the cell's genetic instructions?

Ribosomes- use the information to make proteins

Distributes transport vesicles

Rough ER

membrane factory for cell

Rough ER

Nucleolus

Roughly spherical "sub-organelle" of the nucleus in most animal, fungal, and plant cells

Bright Field Microscopy

Simplest optical microscopy illumination -light passes directly through specimen, then through glass lenses -Very little contrast, specimen is usually stained

Phase-Contrast Microscopy

Specialized optic (rings etched on glass plates) enhance contrast in cells by amplifying variations in sample density No staining needed

Free ribosomes

Suspended in the cytoplasm; make proteins that function within the cytoplasm

What does the ER consist of

System of flattened sacs, cisternae, and inter-connected tubules *Accounts for more than half of the total membrane in many eukaryotic cells

In what ways is the endomembrane system similar to a factory?

The endomembrane system performs so many different functions in the cell that it is often compared to a factory with elaborate assembly lines and shipping capabilities.

What is the ER continuous with?

The nuclear envelope

Some proteins must pass into and out of the nucleus to regulate a variety of activities, including the synthesis of DNA, RNA, and ribosomes. Which of the following pathways would a protein destined for the interior of the nucleus follow?

The protein is translated on free ribosomes and then passes through the pore complex to enter the nucleus.

Who are credited for developing the basic concepts of the cell theory

Theodor Schwann Matthias Schleiden Rudolf Virchow

Process of cell fractionation

Tissue cells-homogenization-homogenate-centrifugation

Side of the golgi apparatus that ships material out

Trans face

Fluorescence Microscopy

UV light is transmitted through a specimen Fluorescently-tagged molecules absorb the UV light and emit visible light

What is cell fractionation

Use of ultracentrifuges to break cells apart and,when dealing with eukaryotic cells, can be used to seperate major organelles from one another

Differential Interference Contrast

Use polarizers to exaggerate differences in the optical density of a specimen Samples have a 3D like appearance

What grows fast volume or surface area?

Volume.. Surface area grows by a factor if n^2 and volume grows by a factor of n^3

Under which of the following conditions would you expect to find a cell with a predominance of free ribosomes? ANSWER: a cell that is secreting proteins a cell that is producing cytoplasmic enzymes a cell that is constructing its cell wall or extracellular matrix a cell that is digesting food particles a cell that is enlarging its vacuole

a cell that is producing cytoplasmic enzymes

what is the centrosome referred to as?

a microtubule organizing center

Which are made of eukaryotic cells? a. protists b. fungi c. animals d. plants e. all of the above

all of the above

All of the following are part of a prokaryotic cell except ANSWER: ribosomes. DNA. a plasma membrane. a cell wall. an endoplasmic reticulum.

an endoplasmic reticulum.

basal body

anchors the cilium or flagellum (9 triplets of microtubules).

carrier proteins

bind to molecules and change shape to shuttle them across

noncompetitive inhibitors

bind to part of an enzyme separate from the active site, causing the enzyme to undergo a conformational change

competitive inhibitors

bind to the active site of an enzyme

study of how organisms manage their energy resources

bioenergetics

How do cells recognize each other

by binding to surface molecules, often carbohydrates, on the plasma membrane

What does hexosaminidase A do?

catalyzes the degradation of fatty acid derivatives known as gangliosides. the gangliosides accumulate in the nerve cells of the brain

steps of phagocytosis

cell engulfs a particle or cell by forming a food vacuole. food vacuole then fuses with a lysosome. enzymes in lysosome break down particle.

microfilaments that function in __ contain the motor protein ___ in addition to actin

cell motility; myosin

what extracellular structure distinguishes animal cells from plants cells

cell wall

extracellular structures

cell walls extracellular matrix intercellular junctions

Cell structure is correlated to ___

cellular function

includes both anaerobic and aerobic respiration

cellular respiration

cell walls are made of ____ embedded in other polysaccharides and protein

cellulose fibers

Where are microtubules nucleated and grown out of in eukaryotic cells?

centrosomes (near the nucleus)

electrochemical gradient

chemical force (ions conentration gradient) and an electrical force (effect of the membrane potential on the ions movement)

the three main kinds of work in cells

chemical, mechanical, and transport

Cargo leaves the endoplasmic reticulum and is sent to the _____ Golgi cisterna, which then matures through the redistribution of enzymes to become a _____ Golgi cisterna and eventually the _____ Golgi cisterna.

cis; medial; trans

an organic cofactor

coenzyme (many vitamins)

a non-protein compound that is bound to an enzyme and required for the enzyme to catalyze a biochemical reaction

cofactor

most abundant ECM glycoprotein. forms strong fibers outside the cells. most abundant protein in animals (25%)

collagen

Golgi Apparatus

consists of cisternae functions as a major shipping and receiving center of cell

aerobic respiration involves

consumption of glucose and oxygen to make ATP

a form of allosteric regulation that can ampilify enzyme activity

cooperativity. stabilizes in favorable conformational form

occurs when active transport of a solute indirectly drives transport pf another solute

cotransport

a network of protein fibers extending throughout the cytoplasm of a cell. Can be quickly disassembled and reconstructed

cytoskeleton

spot-like transmembrane protein-based adhesions that fasten cells together into strong sheets. anchoring junctions

desosomes

pinocytosis

dissolved molecules in the extracellular environment are taken up by the cell when some of the fluid is engulfed in tiny vesicles

lipids in the plasma membrane most often ____ but phospholipids can also ___ but this is rare.

drift laterally; "flip-flop"

motor protein that drives the bending movements of a cilium or flagellum

dynein (has multiple subunits)

transport protein that generates voltage across a membrane

electrogenic pump

The production department of the endomembrane system, where lipids and proteins are made, is the

endoplasmic reticulum (ER).

What are the consecutive steps of protein synthesis?

endoplasmic reticulum-cis Golgi cisternae- medial Golgi cisternae- trans Golgi cisternae- Plasma membrane- extracellular space

isotonic solution

equal concentrations

provides structural support for cells in animals, segregates tissues from one another, and contributes to regulation of intercellular communication

extracellular matrix

bind to transmembrane proteins, integrins, and attach ECM to the cell

fibronectins

as temps drop, the membranes transition from a ___ state to a ___ state

fluid; solid

Scanning electron microscopes (SEMs)

focus a beam of electrons onto the surface of a specimen images with a 3D appearance

Transmission Electron Microscopy (TEMs)

focus a beam of electrons through a specimen. used mainly to study the internal ultrastructure of cells

the energy that is available to do work

free energy

What does the mitochondria contain?

free ribosomes and circular DNA molecules

large and small ribosomal subunits exit the nucleus through nuclear pores and enter the cytoplasm where they are assembled into __ during the stage of protein synthesis

functional ribosomes

cytoplasmic channels between adjacent cells. communicating junctions

gap junctions

In the thylakoid membranes, what is the main role of the antenna pigment molecules?

harvest photons and transfer light energy to the reaction-center chlorophyll

channel proteins

have hydrophilic channels that certain ions or molecules can use to enter or leave the cell

All proteins are synthesized by ribosomes in the cell. Some ribosomes float freely in the cytosol, while others are bound to the surface of the endoplasmic reticulum. Most proteins made by free ribosomes function in the cytosol. Proteins made by bound ribosomes either function within the endomembrane system or pass through it and are secreted from the cell. Which of the following proteins are synthesized by bound ribosomes?

insulin lysosomal enzyme ER protein

proteins that penetrate the hydrophobic cores and often span the entire cell membrane

integral membrane proteins

transmit changes in the ECM to the cytoskeleton

integrins

facilitate cell adherence, interaction,and communication through direct physical contact

intercellular junctions

fibrous proteins supercoiled into thicker cables

intermediate filaments

polymers of intermediate filament proteins, including the protein keratin

intermediate filaments

What two compartments does the inner membrane of mitochondrion create?

intermembrane space mitochondrial matrix

bulk transport

large molecules cross the membrane via vesicles. uses energy

any molecule that binds specifically to a receptor site of another molecule

ligand

at warm temps cholesterol helps ___ movement and at colder temps it helps keep the membrane ____ fluid

limit; more

the temperature at which a membrane solidifies depends on its

lipid composition

Functions of smooth ER:

lipid synthesis carbohydrate metabolism calcium storage detoxification of poisons and drugs- usually with addition of hydroxyl group, making them more soluble

How much cholesterol do plants have?

little to none

Tay-Sachs disease is caused by a ___ disorder.

lysosomal

A ___ is a recycling center in the cell because it breaks down damaged organelles and returns organic monomers to the cytosol.

lysosome

which is more acidic lysosome lumen or cytosol?

lysosome lumen

the voltage difference across the membrane

membrane potential

two intertwined strand of actin filaments

microfilament

forms a 3D network called the cortex just inside the plasma membrane to help support the cell's shape

microfilaments

polymers of protein called actin

microfilaments

polymers of proteins called tubulins

microtubules

the thin layer between primary walls of adjacent cells

middle lamella

which organelles are not part of the endomembrane system?

mitochondria, chloroplasts, and peroxisomes

Energy released by the electron transport chain is used to pump H+ ions into which location?

mitochondrial intermembrane space

Unsaturated fatty acids make membranes ___ fluid than saturated fatty acids

more

Parts of the endomembrane system

nuclear envelope endoplasmic reticulum golgi apparatus lysosomes vacuoles transport vesicles plasma/cell membrane *These are either continuos or connected by transport vesicles

turgid

occurs with a cell wall in a hypotonic solution. wall becomes firm

the hydrophobic regians of integral proteins consist of:

one or more nonpolar amino acids (often coiled into alpha helices)

the active site can lower the activation energy by

orienting/positioning substrates correctly straining the substrates bonds providing a favorable microenvironment covalently bonding to the substrate

the control of solute concentrations and water balance

osmoregulation

Carbon dioxide (CO2) is released during which of the following stages of cellular respiration?

oxidation of pyruvate to acetyl CoA and the citric acid cycle

transfer of electrons between reactants

oxidation-reduction reactions. some redox reactions do not transfer electrons but change the electron sharing in covalent bonds

an enzymes activity can be affected by

pH chemicals temperature

9 triplets of microtubules arranged in a ring that surrounds a pair of centrioles. consists of a "cloud" of amorphous material.

pericentriolar matrix. makes up the centrosome

Proteins that are bound to the surface of the membrane

peripheral membrane proteins

What are food vacuoles formed by?

phagocytosis

some types of cells can engulf other cells and cell debris by ___

phagocytosis

what are the three types of endocytosis

phagocytosis, pinocytosis, receptor-mediated endocytosis

Robert Hooke and Antonie van Leewenhoek

pioneered the advancements in microscopy that the development of the cell theory possible

most cells synthesize and secrete materials that are external to the ___

plasma membrane

channels between adjacent plant cells

plasmodesmata

Types of intercellular junctions

plasmodesmata tight junctions desmosomes gap junctions

most allosterically regulated enzymes are made two or more ___ subunits

polypeptide

cell walls have many sections

primary cell wall middle lamella secondary cell wall plasmodesmata

fermentation

produces ATP through the degredation of sugars without oxygen

the main electrogenic pumps of plants, fungi, and bacteria

proton pumps

the primary cell wall is

relatively thin and flexible

Mitochondrion grow and ____ almost independently in a cell

reproduce

Functions of the nucleolus

ribosomal RNA (rRNA) synthesis assembly of large and small ribosomal subunits (made of rRNA and multiple subunits)

What are ribosomes made of?

ribosomal RNAs and multiple polypeptide subunits

Which organelle of the endomembrane system functions in protein synthesis? The part of the endomembrane system that is studded with ribosomes for protein synthesis is the __

rough ER

found in some cells. added between the plasma membrane and the primary cell wall

secondary cell wall

Chromosome

single DNA molecule associated with proteins

Which type of organelle is primarily involved in the synthesis of oils, phospholipids, and steroids? ANSWER: ribosome smooth endoplasmic reticulum contractile vacuole lysosome mitochondrion

smooth endoplasmic reticulum

major electrogenic pump of animal cells

sodium-potassium pump

hypertonic

solute concentration greater outside of cell

hypotonic

solute concentration is greater inside cell

a transport protein is ___ for the substance it moves

specific

Besides phospholipids, what other lipids are present in the plasma membrane?

sterols

the reactant that an enzyme acts on

substrate

The ATP made during glycolysis is generated by

substrate-level phosphorylation.

to regulate metabolic pathways a cell

switches on or off transcription genes that encode specific enzymes or by regulating activity of enzymes - functional groups can be added to the side chains of specific amino acids in the protein to regulate some enzymes

Endomembrane system

system of internal membranes that partition the cell into organelles

receptor-mediated endocytosis

the binding of ligands to receptors trigger vesicle formation

What does phagocytosis result in?

the formation of a food vacuole in the engulfing cells

what is "work" in a biological system?

the rearrangement of molecules via chemical reactions

Assume a thylakoid is somehow punctured so that the interior of the thylakoid is no longer separated from the stroma. This damage will have the most direct effect on which of the following processes?

the synthesis of ATP

do hydrophilic molecules pass through the plasma membrane easily

they can't pass through without assistance. Includes: ions and large polar molecules

In a plant cell, where are the ATP synthase complexes located?

thylakoid membrane and inner mitochondrial membrane

membranes of neighboring cells are pressed together by interactions between transmembrane proteins, preventing leakage of extracellular fluid

tight junctions

the ability of a solution to cause a cell to gain or lose water

tonicity

metabolism

totality of chemical reactions that occur in a living organsim

integral membrane proteins that span the entire plasma membrane

transmembrane proteins

Membrane- bound sacs within the cell that are larger then vesicles

vacuoles

Like a shipping container or truck, a_____ transports materials between various parts of the endomembrane system.

vesicle

How does a light microscopy work?

visible light passes through a specimen and then through glass lenses, magnifying the image.

Peroxisomes convert H2O2 to ____ and ____

water and oxygen

What can pass through plasmodesmata

water, small solutes, and sometimes proteins and RNA

plasmolysis

when the cell membrane pulls away from the wall when the cell is in a hypertonic environment

Do mitochondria have a smooth outer membrane and an inner membrane folded into cristae?

yes

is NAD+ a coenzyme?

yes

do hydrophobic molecules pass through the plasma membrane easily?

yes, dissolve in the lipid bilayer and pass through membrane rapidly. (hydrocarbons)

can proteins move in the plasma membrane?

yes, they are slower than lipids

are living organisms considered open systems?

yes. lose a lot of energy by heat