BIOL 150 Test 2 Flashcards
What are the three components of the cell theory?
- Cells are the smallest living things
- Cells arise only by the division of a previously existing cell
- All living organisms are composed of one or more cells
Explain why cell size is limited
Cell size is limited because it has to diffuse substances into and out of the cell. The rate of diffusion is affected by (1) SURFACE AREA AVAILABLE FOR DIFFUSION (2) temperature, (3) concentration gradient of diffusing substance, and (4) the distance over which diffusion must occur (thickness of membrane). AS THE SIZE OF A CELL INCREASES, ITS VOLUME INCREASES MUCH MORE RAPIDLY THAN ITS SURFACE AREA, THEREFORE THE LENGTH OF TIME FOR DIFFUSION FROM THE OUTSIDE MEMBRANE TO THE INTERIOR OF THE CELL INCREASES AS WELL.
Describe the change in surface area to volume ratio as cells increase in size
For a spherical cell, the surface area is proportional to the square of the radius while the volume is proportional to the cube of the radius.
List the four structural similarities found in cells
- A nucleoid or nucleus where genetic material is located
- Cytoplasm
- Ribosomes to synthesize
- A plasma membrane
Compare the characteristics of eukaryotic and prokaryotic cells as shown in the table
Prokaryotes - have DNA in nucleoid region, are smaller in size, usually single-celled, may not need oxygen, and has no membrane-bound organelles
Eukaryotes - have DNA inside membrane-bound nucleus, are larger in size, often multicellular, usually need oxygen to exist, have membrane-bound organelles
Cell wall and cell membrane differences between bacterial and archaeal cell types
Bacterial Cells -
cell wall composed of peptidoglycan (carbohydrate matrix cross-linked with short polypeptide units)
cell walls protect the cell, maintain shape, and prevent excessive uptake/loss of water
Archaeal Cells -
cell wall made of polysaccharides, proteins, and sometimes inorganic components
membrane lipids include saturated hydrocarbons covalently attached to glycerol at both ends (forms a monolayer membrane)
membranes confer greater thermal stability (but cannot alter degree of saturation, therefore limiting response to changing environmental temperatures)
Plasma Membrane
Regulates what passes into and out of the cell; cell-to-cell recognition; connection and adhesion; cell communication
Nucleus
Instructions for protein synthesis and cell reproduction; contains genetic information
Chromosomes
Contain hereditary information used to direct synthesis of proteins
Nucleolus
Synthesis of rRNA and ribosome assembly
Ribosomes
Sites of protein synthesis
Endoplasmic Reticulum (ER)
Intracellular compartment forms transport vesicles; participates in lipid synthesis and synthesis of membrane or secreted proteins
Golgi Apparatus
Packages proteins for export from cell; forms secretory vesicles
Lysosomes
Digest worn-out organelles and cell debris; digest material taken up by endocytosis
Microbodies
Isolate particular chemical activities form rest of cell
Mitochondria
“Power plants” of the cell; sites of oxidative metabolism
Chloroplasts
Sites of photosynthesis
Cytoskeleton
Structural support; cell movement; movement of vesicles within cells
Flagella (cilia)
Motility or moving fluids over surfaces
Cell Wall
Protection; support
Cell walls are present in
prokaryotes and plants
Cell membranes are present in
prokaryotes, animals, and plants
Flagella/cilia are present in
flagella may be present in prokaryotes, both may be present in animals (9 + 2
structure), and both are absent in plants except in sperm of a
few species (9 + 2 structure)
Endoplasmic reticulum is present in
usually present in plants and animals
Ribosomes are present in
plants and animals
Microtubules are present in
plants and animals
Centrioles are present in
animals
Golgi Apparatus is present in
plants and animals
Nucleus are present in
plants and animals
Mitochondria are present in
plants and animals
Chloroplasts are present in
plants
Chromosomes are present in
prokaryotes as a single circle of DNA; animals as multiple DNA-protein complex; plants as multiple DNA-protein complex
Lysosomes are present in
Usually present in animals, and present in plants
Vacuoles are present in
absent or small in animals; usually a large single vacuole in plants
Explain how a protein is transported through the endomembrane system
Proteins are manufactured in the rough and smooth ER membranes and then transported to the Golgi apparatus, being modified as they pass through it. The most common alteration performed by the Golgi apparatus is adding short sugar chains, forming glycoproteins (existing glycoproteins can also be altered by adding or modifying sugars). These are then packaged into vesicles that pinch off from the trans face of the Golgi. These vesicles diffuse to other locations in the cell, distributing the newly synthesized molecules to their appropriate destinations.
Describe the probable origin of mitochondria and chloroplasts
Mitochondria and chloroplasts arose by endosymbiosis. This thoery proposes that these organelles and some other eukaryotic cells evolved from a symbiosis between different species of prokaryotes that were each free-living. I.e., one cell, a prokaryote, was engulfed by and became part of another cell.
As a cell increases in size, the surface area increase _______ than the volume.
less
The surface area of a cell increases proportionally to the radius ______
squared
The volume of a cell increases proportionally to the radius _____
cubed
Protein processing pathway
1) Vesicle containing proteins buds from the rough endoplasmic reticulum, diffuses through the cell, and fuses to the cis face of the Golgi apparatus.
2) The proteins are modified and packaged into vesicles for transport.
3) The vesicle may travel to the plasma membrane, releasing its contents to the extracellular environment.
Know parts of
endomembrane system
mitochondria
chloroplasts
phospholipid
kk
The evolutionary process that created chloroplasts and mitochondria is
endosymbiosis
Microfilaments such as actin, microtubules, and the intermediate filaments form the cell-supporting structure called the
cytoskeleton
Integrins are glycoproteins that help link the cytoskeleton and the
extracellular matrix
Organelles that breakdown hydrogen peroxide into water and oxygen are
peroxisomes
A circular molecule of DNA devoid of any histone proteins describes the chromosome of a (an)
bacteria
Prokaryotic cell movement is attributed to
flagella
The eukaryotic organelle that is directly involved in the transport of proteins synthesized on the surface of the rough ER is called the
golgi apparatus
In eukaryotes, mitochondria are the organelles primarily involved in
energy release/capture
Plant cells often have a large membrane-bound sac that is used for storing water and other substances called a
central vacuole
Mitochondria and chloroplasts are the other organelles besides the nucleus that contain
DNA
You stain a cell with a dye that reacts with an enzyme found in the lysosome. You would also expect to see this dye in the
endoplasmic reticulum
Sulfolobus are archaea that are commonly found in geothermal environments, with an optimum growth temperature of about 80°C. What feature allows archaea to thrive at such temperatures?
Archaeal membranes contain special lipids
A protein that is destined to reach the plasma membrane is making its way through the Golgi. At that moment, a drug was added to cells, blocking trafficking at the trans face of the Golgi. As a result, what would happen to the protein?
The protein would be stuck in the Golgi.
Based on the function of mitochondria, what substance is able to pass through the outer membrane of the mitochondria easily?
oxygen
Individuals that are heavy smokers may eventually have trouble clearing the mucous from their lungs because the structures that move fluid along the epithelial lining of the lung become damaged over time. What are these structures called?
cilia
Streptomycin is an antibiotic that interferes with the function of the 30S subunit of the prokaryotic ribosome. What is the consequence of treating a bacteria with streptomycin?
impaired protein synthesis
A dish of cells is treated with centrinone, a centriole inhibitor. These cells would no longer be able to _________.
divide
As ATP moves from the matrix of the mitochondrion to the cytoplasm of a cell, how many membranes will it pass?
2
How do membranes form spontaneously?
The hydrophobic fatty acid tails on phospholipids are repelled by water.
Glucose is taken up by red blood cells by binding to a specific pocket in a membrane protein which then allows it to cross the membrane and move down its concentration gradient. What would be the best definition of this process?
Facilitated diffusion using a transporter
Exocytosis
Exocytosis is a process that occurs when a cell moves large materials from inside the cell to the outside of the cell using small spheres of membrane called vesicles. This process is a form of active transport, meaning it uses energy.
The hormone insulin is a protein produced in the pancreas and then secreted into the blood stream after a meal to increase glucose uptake by tissues. What cellular process is used to secrete insulin from the pancreas?
exocytosis
What describes the movement of substances down their concentration gradients?
Diffusion
Osmosis is the diffusion of water across a membrane in response to the concentration of one or more of the ______.
solutes
In a single pump cycle where sodium and potassium are exchanged and ATP is used, the following is expected
3 sodium ions leave and 2 potassium ions enter
A type of molecule movement of that is specific and passive and becomes saturated if all of the protein carriers are in use
facilitated diffusion
Receptor-mediator endocytosis
Receptor-mediated endocytosis, also called clathrin-mediated endocytosis, is a process by which cells absorb metabolites, hormones, proteins – and in some cases viruses – by the inward budding of the plasma membrane.
