Chapter 1: What is a cell?
Terms in this set (69)
fundamental unit of life. They are self-replicating structures that are capable of responding to changes in their environment.
a trait that is exhibited by molecules that work together; it can generate nearly exact copies of itself and is self-correcting.
consist of cell membranes enclosing a compartment called cytosol.
Second law of thermodynamics
Every energy transfer or transformation increases the entropy of the universe.
the simplest form of cells. The cells can come together to form biofilms. They may have a cell wall for rigidity. Only has one type of membrane -- the plasma membrane. They do not form complex multicellular organisms. And the Genetic information is in a single circular chromosome called a plasmid.
are complex cells capable of forming multicellular organisms.
A network of membranes inside and around a eukaryotic cell, related either through direct physical contact or by the transfer of membranous vesicles.
regulates protein traffic and performs metabolic functions in the cell;
bacteria and archaea
prokaryotes that do not have membrane-bound organelles and have plasmids.
Domain of unicellular prokaryotes that have cell walls that do not contain peptidoglycan; they are typically extremophiles because they live in environments that have low oxygen, high pressure, or extreme temperatures.
Thought to be an intermediatory form.
archaea and eukaryotic cells
read and translate genetic information with RNA polymerase and ribosomes.
the key invention which produced an understanding that cells are the basic unit of life and initiated the process of understanding how they function.
coined the term "cell" when examining a piece of cork (dead cells, remnants of cell wall)
schleiden and schwann
undertook a comprehensive survey of tissues to show that all consisted of cells. Created the cell theory.
idea that all living things are composed of cells, cells are the basic units of structure and function in living things, and new cells are produced from existing cells
Hypothesis stating that life could arise from nonliving matter; hypothesized by aristotle.
disproved spontaneous generation by using the swan neck bottle.
"Swan Neck Bottle Experiment"
Louis Pasteur sterilized some substance and realized that if it was sealed no bacteria would grow on the substance. Advocates of spontaneous generation, however, said that by heating the substance it killed the "forces in the air" that made spontaneous generation occur, thus no bacteria grew on the substance. Pasteur then made the swan-neck bottle and put broth and heated it. The broth did not get contaminated even though the swan neck allowed air to come through and the heat did not touch the air, disproving that the air had forces. The spores in the air were in the neck of the bottle. Once pasteur washed the bottle or cut off the neck, the broth became contaminated.
light is below the specimen. The light shines through the condenser lens, which focuses light on to the specimen. The disadvantages of using this is that most cells don't have very good refractive properties, the structures in the cells look similar to water, cells have to be stained, and we have to use polarized light to enhance refractive properties of the cell.
cells are excited with light of a short wavelength (one wavelength), this increases the energy. This then hits a fluorescent molecule in the specimen; this particle then emits light of a longer wavelength.
coincides with 2nd law of thermodynamics.
instead of illuminating the specimen with light from underneath like the brightfield microscope, the illuminating light is through the objective lens.
the light source goes through the objective lens, hits the object, and then the light passes through the beam-splitting mirror and goes into the eyepiece where we can see.
Laser scanning confocal microscope
-more sophisticated than fluorescence microscope
- scans a tightly focused laser beam over the specimen and filters out light that comes from outside of the focal plane.
-very sharp images are assembled from these scans by computer and the focal planes can be assembled into 3D Images.
-pinhole aperature allows only only fluorescence emitted from the exact point of focus to be emitted.
Disadvantage: cannot see small objects.
have a higher resolving power, so one can see smaller objects; wavelength of the electron is smaller than the wavelength of light.
focuses a beam of electrons and magnetic coils (instead of a beam of light like the brightfield microscope) on the specimen and detects the electrons which pass through it.
-- the specimen must be very thin
-- offers valuable information on the inner structure of the sample, such as crystal structure, morphology, and stress state information
scans a beam of electrons over the surface of the specimen and detects the electrons, which are scattered back, to compile a surface view of the structure.
creates a pseduo-3D structure.
-- information on the sample's surface and its composition.
semipermeable barrier between a cell and the external environment. It allows cells to create an environment that is distinct from the outside world. It consists of lipid bilayer in which proteins are suspended.
hydrophobic molecules and small neutral molecules, CO2, and water
diffuse through the membrane without the help of a protein
polar organic molecules, ions, and proteins
cannot diffuse through the membrane; need the help of a protein.
form a selective "pore" through a membrane that permits specific molecules to pass through.
capture molecules on one side of a membrane, then change shape to allow the molecules to pass through it.
function much like carrier proteins, but require the input of energy, usually in the form of ATP hydrolysis.
attach cells to each other and the extracellular environment, and receive and transmit signals.
storehouse of genetic information.
inner and outer; penetrated by nuclear pores allowing entry and exit from the nucleus; regulated entry/exit and protects DNA
torn apart during mitosis and meiosis.
where ribosomal genes are produced.
DNA not needed for transcription is protected in this compacted state. stains dark.
The less condensed form of eukaryotic chromatin that is available for transcription.
build food molecules from carbon dioxide and water using light energy.
pump protons to generate energy
converts food to cellular energy and generate CO2 and H2O.
pump protons to generate energy.
a stack of thylakoids
A flattened membrane sac inside the chloroplast, used to convert light energy to chemical energy.
where light energy is captured and converted into cellular energy.
fluid portion of the chloroplast; outside of the thylakoids
part of mitochondrion that is the location of high-energy compounds are converted into ATP
part of mitochondrion where enzymes convert food molecules into small, high-energy compounds.
outer membrane of mitochondria
derived from primitive plasma membrane.
inner membrane of mitochondria
the remains of prokaryotic membrane.
Vesicles in transit from one part of the cell to another.
Smooth Endoplasmic Reticulum
involved in lipid synthesis and calcium storage and release.
rough endoplasmic reticulum
coated with ribosomes that synthesize proteins inserted across the membrane as they are synthesized.
synthesizes membrane phospholipids and is where secreted proteins and many membrane proteins are synthesized. They are then carried to the golgi apparatus.
A system of membranes that modifies and packages proteins for export by the cell; for example, adding sugars, phosphate groups, or sulfate groups to amino acids in the proteins.
after this, the cell can fuse with membrane, secrete to the extracellular environment, or they can go to lysosomes to be degraded.
A network of fibers that holds the cell together, helps the cell to keep its shape, and aids in movement
protein fibers that play a role in cell division and shape; smallest
generate structure for the membrane. (the skeletal system of the cell)
interact with motor proteins that generate force and move components around; largest; muscle system of the cell. help with cell division.
sheets of cells attached to each other and the extracellular environment, and form selectively permeable barriers between distinct body compartments.
layers of epithelial tissue that is exposed to environment. i.e exposed to the lumen of the gut.
layers of epithelial tissue that is attached to basement membrane surfaces.
formed by individual cells embedded in the extracellular environment and provide structural stability to organs. ex: bones.
provides the force necessary to move the body, pump blood, and contract the intestine;
generates action potentials.
provides rapid communication between body parts in animals
generates action potentials.
cytoskeletal protein found in muscle .
thick filament; motor protein found in muscle.
stimulated by the nervous system; voluntary movement.
involuntary muscle tissue found only in the heart. It is stimulated by another muscle cell; It is connected via gap junctions.
have actin and myosin in different orientations; found in blood vessels and muscles that require expansion and contraction.
shows basic molecular biology of gene propagation and expression.
shows eukaryotic molecular biology (transport through the endomembrane system and cell cycle control)
The wall cress
shows plant molecular biology and development.
The Fruit Fly, a round worm, zebra fish, and mouse
shows a genetic analysis of animal molecular biology and development.