Chapter 1 Flashcards
All cells are enclosed by a
plasma membrane
Animal and plant cells are usually _ in diameter and can be seen with a _
5-20 nanometers, light microscope
What microscope reveals even the smallest organelles but specimens require elaborate preparations and cant be viewed alive
Electron
Specific large molecules can be located in fixed or living cells by
fluorescence microscopy
Simplest present day living cells are
prokaryotes
Classes of prokaryotes
bacteria and arachaea
Prokaryotes contain DNA but
lack nucleus and most other organelles, resembling ancestral cell
Contains main genetic info of eukaryotic organisms, stored in very long DNA
Nucleus
The — of eukaryotic cells includes all of the cell’s contents outside the nucleus and contains a variety of membrane-enclosed organelles with specialized functions
cytoplasm
carry out the final oxidation of food molecules and produce ATP
Mitochondria
synthesize complex molecules for export from the cell and for insertion in cell membranes
Golgi and ER
digest large molecules
Lysosomes
Outside the membrane-enclosed organelles in the cytoplasm is the ___, a highly concentrated mixture of large and small molecules that carry out many essential biochemical processes.
cytosol
The cytoskeleton is composed of
protein filaments that extend throughout the cytoplasm a
Protein filaments are responsible for
cell shape and movement and for the transport of organelles and large molecular complexes from one intracellular location to another
Free-living, single-celled eukaryotic microorganisms are complex cells that
can swim, mate, hunt, and devour other microorganisms
What is the central dogma
All cells store genetic information as DNA,
Information flows from DNA to RNA (transcription) and from RNA to protein (translation)
Plasma membrane characteristics
Lipid bilayer, permeable, hydrophobic interior, hydrophilic exterior
New cells are formed from pre existing cells proposed in the
1830s
Can also observe some sub-cellular structures or organelles (e.g. nucleus) by
light microscopy
With thin samples, one can study unstained, living cells by
light microscopy
low contrast images in living cells, often fix and stain cells to add contrast
Bright field
Phase contrast & differential interference contrast look at structures that
refract light
optical sectioning of thicker samples with laser
beam
Confocal fluorescence microscopy
microscopy allows higher magnification of fixed cells
electron
Used to look at very thin sections of cells
This allows detection of more sub-cellular organelles
TEM
Used to look at surface details of cells
Scanning electron microscopy (SEM)
Cell walls are common and greater diversity and habitat of
prokaryotes
Smaller genomes in
prokaryotes
eukaryotic cells have both
protists (single cell) and multcell
Eukaryotic cells are __ than prokaryotic cells
larger and more regulatory DNA sequences
Largest organelle
Nucleus
Nucleus is surrounded by a double membrane known as
nuclear envelope
In the nucleus there’s traffic in and out of nucleus regulated by
nuclear pores
DNA is packaged with — into chromosomes
proteins
site of DNA replication and transcription, RNA processing, ribosome assembly
nucleus
often breaks down and chromosomes condense during cell division
nuclear envelope
present in nearly all eukaryotic cells
mitochondria
Mitochondria are _ membrane structures and chloroplasts are __ membrane structures
double, triple
what organelles contain their own DNA and reproduce by division
mitochondria and chloroplast
Mitochondria evolved from
bacteria engulfed by ancestor cells
perform cellular respiration, generate ATP and O2 and CO2 as byproduct
mito
chloroplasts are only present in
plants and algae
Third membrane of chloroplast contains
chlorophyll
Chloroplasts perform photosynthesis, use _ and _, sunlight to make __, __, and release _
CO2, H20, sugars, ATP, O2
network from nuclear envelope throughout cytoplasm
ER
has bound ribosomes, and is the site of synthesis of transmembrane proteins
rough ER
does not have bound ribosomes; it is the site of steroid hormone synthesis
and Ca2+ uptake
smooth ER
a stack of flattened membranes near the nucleus
GOLGI
Golgi function
- receives and modifies molecules made in the ER
- packages them for delivery to other locations or to the plasma membrane for secretion
small, irregularly shaped organelles, sites of intracellular digestion
Lysosomes
small membrane-enclosed organelles, contained environment for the generation and degradation of toxic molecules
Peroxisomes
- transport from plasma membrane inward is called
- transport to the plasma membrane for secretion is called
endocytosis, exocytosis
endocytosis and exocytosis are performed by
transport vesicles
non-membrane containing cytoplasm
cytosol
filamentous proteins that provide structural framework for cell
cytoskeleton
Three filaments
actin, intermediate, microtubule
filament used for contraction and transport
actin-based
filament used for mechanical stabilization
intermediate based filament
filament used for support and transport
microtubule
E. coli bacteria are the premier model for
prokaryotes
Advantages of E.Coli as a model organism vs disadvant.
Can grow cheaply in simple media, reproduces rapid, small genome
Not a euk
E coli used to study
DNA replication and genetic code
Saccharomyces cerevisae & Schizosaccharomyces pombe advantages as a model organism
simple, easy to grow and rapid generation, carries out basic cell functions, good genetics
Saccharomyces cerevisae & Schizosaccharomyces pombe used to study
organization of chromosomes and cell division cycle
Arabidopsis thaliana (wall cress) advantages
small genome size for plant, can grow inside, generation time is 8-10 weeks
Arabidopsis thaliana (wall cress) are a good model for
multi-cellular plant development, photosynthesis
Drosophila melanogaster (fruit fly) Advantages
easily grown in lab, many genetic mutants available, genome size is 185 million bp and has counterparts for genes in human disease
C. elegans (nematode worm)
Advantages
slightly smaller and simpler than Drosophila, worm counterparts exist for ~70% of human genes
C. elegans are a good model for
animal development and apoptosis
zebrafish advantages
easily maintained in freshwater and transparent embryos
useful for study of early development in live animal
zebrafish
good model for mammalian development and disease
mouse
advantages of mice
can be generated with many mutations, closely related to human genes, rapid generation
appearence and behavior of cells dictated largely by
proteins
what gives proteins a different conformation
amino acids
What cannot reproduce by their own efforts and arent living
Virus
entire sequence of nucleotides in an organisms DNA provides a genetic program for cells to behave
Genome
Differentiated cell types are generated during
embryonic development
dense material often made of protein fibers embedded in a gel of sugar chains
ec matric
RNA translation into proteins
ribosome
have no organelles only ribosomes
bacterium
prokaryote shapes
spherical, rod, spiral
2 concentric membranes continuous with the ER membrane
nuclear evelope
breaks down ingested cellulose and makes methane gas
archaea
what kind of proteins use energy stored in ATP, carrying organelles and proteins through cytoplasm
motor
What structure in an interphase cell contains ribosomal rRNA and proteins for the formation of ribosomes?
nucleolus
Cell biologists employ targeted fluorescent dyes or modified fluorescent proteins in both standard fluorescence microscopy and confocal microscopy to observe specific details in the cell. Even though fluorescence permits better visualization, the resolving power is essentially the same as that of a standard light microscope because the resolving power of a fluorescent microscope is still limited by the __________________ of visible light.
wavelegnth
Ability to perceive the presence of an object
Detection
Ability to discriminate between two objects that are close together, limited by wavelength of light
Resolution
The bright field image of live cell allows us to see
The nucleus and a few large organelles
Blue stains dye what molecules
Negatively charged molecules such as DNA and RNA
Flourescent microscopy allow us to see
Nucleus, pigment granules, and micro tubules
You can see nucleus and mitochondria by
Light microscopy and fluorescent microscopy
Interphase consists of what phases
G1, S phase (dna replication), and G2
Mitochondria are located at sites of
High energy consumptions
ER extends from the
Outer membrane of nuclear envelope
Flexible strands with tensile strength
Actin filaments
Hollow tubes that serve as rigid struts and organize compartments
Micro tubules
Rope like strands that provide mechanical support
Intermediate filaments
Chromosomes attach to micro tubules by their
Kinetochores
With our eyes we can see what micrometer amount
200
Red blood cell size
7 um
Need __ to resolve smaller organelles
electron microscopy or super- resolution fluorescence microscopy
Mitochondria makes ATP via
Respiration
Converts pyruvate and fatty acids into ATP, CO2, and H2O
Respiration
What forms the miotic spindle
Microtubules
