Cells Flashcards
The smallest unit of organization that can perform all activities required for life.
cell
A structural polysaccharide of plant cell walls, consisting of glucose monomers joined by b glycosidic linkages.
cellulose
A protective layer external to the plasma membrane in the cells of plants, prokaryotes, fungi, and some protists.
cell wall
A structure in the centrosome of an animal cell composed of a cylinder of microtubule triplets arranged in a “9+0” pattern.
centriole
An adenine containing nucleoside triphosphate that releases free energy when its phosphate bonds are hydrolyzed. This energy is used to drive endergonic reactions in cells.
ATP or Adenosine Triphosphate
A green pigment located in membranes within the chloroplasts of plants and algae in the membranes of certain prokaryotes.
Chlorophyll
A eukaryotic cell structure consisting of a “9+0” arrangement of microtubule triplets. It may organize the microtubule assembly of a cilium or flagellum and is structurally very similar to a centriole.
Basal Body
A network of microtubules, microfilaments, and intermediate filaments that extend throughout the cytoplasm and serve a variety of mechanical, transport, and signaling functions.
Cytoskeletal System
The semifluid portion of the cytoplasm.
cytosol
A nucleic acid molecule, usually a double stranded helix, in which each polynucleotide strand consists of nucleotide monomers with a deoxyribose sugar and the nitrogenous bases adenine, cytosine, guanine, and thymine.
Deoxyribose Nucleic Acid (DNA)
What is the theory that the mitochondria and plastids, including chloroplasts, originated as prokaryotic cells engulfed by a host cell? The engulfed cell and its host cell then evolved into a single organism.
Endosymbiotic Theory
What is the type of cell with a membrane enclosed nucleus and membrane enclosed organelles?
Eukaryotic cells
The contents of the cell bounded by the plasma membrane; in eukaryotes, the portion exclusive of the nucleus.
cytoplasm
What is the meshwork surrounding animal cells, consisting of glycoproteins, polysaccharides, and proteoglycans synthesized and secreted by the cells?
Extracellular Matrix
What is the long cellular appendage specialized for locomotion?
flagellum
What is the organelle in eukaryotic cells consisting of stacks of flat membranous sacs that modify, store, and route products of the endoplasmic reticulum and synthesize some products, notably non-cellulose carbohydrates?
Golgi Body
What is the term for having no affinity for water; tending to coalesce and form droplets in water?
hydrophobic
What is the term for having an affinity for water?
Hydrophilic
What is the component of the cytoskeleton that includes filaments intermediate in size between microtubules and microfilaments?
intermediate filaments
A membrane enclosed sac of hydrolytic enzymes found in the cytoplasm?
Lysosome
What is the organelle in eukaryotic cells that serves as the site of cellular respiration; uses oxygen to break down organic molecules and synthesize ATP?
mitochondria
What is the organelle in eukaryotic cells that serves as the site of cellular respiration; uses oxygen to break down organic molecules and synthesize ATP?
mitochondria
What is the type of motor protein that associates into filaments that interact with actin filaments to break down organic molecules and synthesize ATP?
Myosin
What is the non-membrane enclosed region in a prokaryotic cells where its chromosome is located?
nucleoid
What is the organelle of a eukaryotic cell that contains the genetic material in the form of chromosomes, made up of chromatin?
nucleus
What is the membrane at the boundary of every cell that acts as a selective barrier, regulating the cell’s chemical composition?
plasma membrane
What is the complex of rRNA and protein molecules that function as a site of protein synthesis in the cytoplasm, consists of a large and small subunit?
ribosomes
What is the portion of the endoplasmic reticulum that is free of ribosomes?
Smooth Endoplasmic Reticulum
What is the membrane-bound vesicle whose specialized function varies indifferent kinds of cells?
vacuole
What is the small hair like structures used for movement or sensing things?
cilia
What is the type of intercellular junction that directly connects the cytoplasm of neighboring plant cells to each other, establishing bridges between cells?
plasmodesmata
What is a type of intercellular junction in animal cells that function as a rivet, fastening cells together?
desmosomes
What is the main use of integrins?
to transmit signal between ECM and cytoskeleton.
What is the purpose of tight junctions?
Creates a barrier in which molecules can’t pass through. E.g. prevent leakages of digestive enzymes.
What are microtubules for?
shapes the cell, guides movement of organelle, monorails, separates chromosomes during cell division.
Where are microtubules organized at?
centrosome
What are the parts of microtubules?
- Attached to plasma membrane - most of the time it is outside of the cell
- A basal body that anchors the cilium or flagellum
- Motor Protein - dynein allows bending movement
Why is there a twisting double chain of actin subunits in Microfilaments?
To bear tension and resists pulling forces within the cell
What are the proteins that cause cell contraction?
myosin + actin
Give examples in which microfilaments are used.
Amoeba movement and Cytoplasmic streaming
What is the type of filament that gives a more permanent cytoskeleton fixture than the other two?
intermediate filament
What are the three postulates of the cell theory?
- All living things are composed of cells.
- The cell is the basic unit of life.
- Cells arise from pre-existing cells.
Why are cells so small?
Faster transportation of nutrients, energy, efficient cell communication and processes.
What is the main differences between eukaryotic and prokaryotic cells?
Eukaryotic cells: membrane bound organelles, nucleus, bigger
Prokaryotic cells:
doesn’t have membrane bound organelles, smaller, nucleoid, no nucleus
What do eukaryotic and prokaryotic cells have in common?
ribosomes, cell membrane, cytosol, chromosomes
What is the difference between cytosol and cytoplasm?
Cytosol is the gel-like substance itself, cytoplasm include the organelles
Why are eukaryotic cells bigger?
they carry organelles
What does a rough ER mean?
has ribosome present –> more active in protein synthesis
What does Smooth ER mean?
no ribosomes present –> active in lipid synthesis
What is the packaging center?
Golgi Body
Examples of eukaryotic cells:
animals, fungi, protists (amoeba)
What shape is the eukaryotic cell’s DNA?
Double Helix
What shape is the prokaryotic cell’s DNA?
Plasmid (circular)
Are all prokaryotic cells unicellular?
yes.
How do you know a bacteria is pathogenic?
Hemolysis: complete rupture of red blood cells (blood becomes more translucent)
Describe the plasma-membrane:
- phospho-lipid bilayer
- semi-permeable
- double layer of phospholipids
- heads - hydrophilic
- tails - hydrophobic
What system regulates protein traffic and performs metabolic functions in the cell?
Endomembrane System
Describe Endoplasmic Reticulum.
Smooth ER - lipid synthesis
Rough ER - protein synthesis
What are the different part of the Golgi Body?
Cis (receiving), cisternae (modifies ER products/proteins), Trans face (shipping)
What are lysosomes for?
To clean out damaged cells
What do lysosomes contain that allows them to hydrolyze proteins, polysaccharides, lipids, DNA, and RNA?
hydrolytic enzymes
What is phagocytosis?
when a cell engulfs another cell
What is autophagy?
cleaning out damaged cells
What are the three kinds of vacuoles?
food, contractile, central
What are the parts of a mitochondria?
- Outer membrane - permeable; exchanges of metabolites occur here
- Inner membrane - contains ribosomes and DNA of mitochondria; contains the ETC and ATP synthase
What are chloroplasts?
site of photosynthesis, has chlorophyll
Which organelles are independent of the endomembrane system?
mitochondria, chloroplast, peroxisome
Where are peroxisomes found?
Eukaryotic cells
What do peroxisomes specialize in? How are they different in lysosomes?
They produce hydrogen peroxide for oxidative purposes.
Why are organelles compartmentalized?
So that they could do their tasks simultaneously without disrupting each other’s processes.
What happens if the plasma membrane is permeable?
it will lyse
Where can you find ribosomes?
Cytosol (free ribosomes), ER, Nuclear Envelope (bound ribosomes)
Where is protein synthesis carried at?
Ribosomes
What is the difference between vacuoles vs vesicles?
a. Vesicle - transport
b. Vacuoles - storage (usually bigger)
What is the importance of the enfolding of the mitochondria?
Increase surface area -> concentration of protons
Can changes in mitochondrial DNA affect health and development?
Efficiency of generating energy (ATP) -> Brain (uses a lot of energy), Muscles (muscle weakness and atrophy )
What molecule do we use for oxidation?
Oxygen
In the fractionation of homogenized cells using differential centrifugation, which of the following will require the greatest speed to form pellets at the bottom of the tube?
Ribosomes
A cell with a predominance of rough endoplasmic reticulum is most likely ________.
Producing large quantities of proteins for secretion.
Cells are ____.
Characteristic of prokaryotic and eukaryotic organisms.
Prokaryotes are ___ than eukaryotes.
Smaller
Cell crawling involves what?
Growth of actin filaments to form bulges in the plasma membrane.
What is the primary function of integrins?
Transmit signals from the extracellular matrix to the cytoskeleton
Describe the movement of the cilia and flagellum. How does that happen?
Movement of cilia and flagella is a result of motor proteins causing microtubules to move relative to each other
Structure that is common to plant and animal cells?
Mitochondrion
Prokaryotes examples.
Bacteria and Archaea
Which of the ff. structure form cytoplasmic channels that connect adjacent plant cells through cell walls?
plasmodesmata
Tay-Sachs disease. Cells accumulate and become clogged with large, complex, undigested lipids. Which organelle is defective?
lysosome
Which organelle takes up much of the volume of a plant cell?
Central vacuole
A unicellular organism found to contain a cell wall, plasma membrane, two flagella and peroxisomes. What organism is it?
Motile eukaryote; prokaryotes don’t contain peroxisomes ang lysosomes
Function of nuclear pore complex in eukaryotes?
Regulates movement of proteins and RNAs in and out
Which organelle is the primary site of ATP synthesis in eukaryotic cells?
Mitochondria
What does a high density of ribosomes in cytoplasm mean?
Cell is actively producing proteins
Explain Transmission Electron Microscope (TEM).
Electron beams have shorter wavelengths than visible light
What structure is independent of the endomembrane system?
Chloroplast and Mitochondria
Which macromolecule leave the nucleus of a eukaryotic cell?
mRNA
Where is DNA found in bacteria?
Nucleoid
Predominance of smooth ER means what?
Cell specializes in synthesizing lipids
Which imposes a limit on cell size?
Ratio of surface area to volume
Which cell would be best for studying lysosomes?
Phagocytic white blood cells.
Smallest structure that would most likely be visible with a standard microscope?
mitochondrion
What type of cell utilizes DNA but do not have it encased with a nuclear envelope?
Archaean
What is abundant in liver cells?
Smooth ER
Why do Cilia and Flagella bend?
Motor protein - dynein
The 3 people who contributed to the cell theory.
Matthias Schleiden
Theodor Schwann
Rudolf Virchow
