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