Cell Intro Flashcards
What did Matthias Schleiden and Theodor Schwann do
- determined that cells are the universal building blocks of all living tissue
- this led to modern cell theory
how dod Schleiden and Schwann come to their discoveries
through examination of plant and animal tissues
what are the elements of cell theory
- cells are the basic unit of life
- all living organisms are composed of one or more cells
- new cells are generated only from preexisting cells
do cells look different based on their function
yes
what have prokaryotic cells
- bacteria
- archaea
what have eukaryotic cells
- plant
- animal
- fungi
- protists and other complex unicellular organisms
describe the differences in nuclei between prokaryotes and eukaryotes
- prokaryote absent
- eukaryote present
describe the differences in cell size between prokaryotes and eukaryotes
- prokaryote 1um
- eukaryote 10-100um
describe the differences in structure between prokaryotes and eukaryotes
- prokaryote unicellular
- eukaryote mostly multicellular, some unicellular
describe the differences in cytoskeleton between prokaryotes and eukaryotes
- prokaryote simple
- eukaryote complex
describe the differences in membrane-bound organelles between prokaryotes and eukaryotes
- prokaryote absent
- eukaryote present
describe the differences in DNA content between prokaryotes and eukaryotes
- prokaryote 1-5 million base pairs
- eukaryote 15 million to 5 billion base pairs
describe the differences in chromosomes between prokaryotes and eukaryotes
- prokaryote circular, single
- eukaryote linear, multiple
where is DNA found in prokaryotic cells
- no nucleus present
- found in distinct areas
where are ribosomes found in prokaryotic cells
free in cytoplasm
describe the envelope of a prokaryotic cell
- inner plasma membrane
- peptidoglycan cell wall
- lipopolysaccharide outer membrane (in some cases)
describe a key feature of dictyostelium discoideum
- unicellular
- when nutrients are scarce, they turn into a multicellular “slug” to go look for food
describe the internal membranes of eukaryotic cells
- lots of membranes (both internal and external)
- internal membranes organize and create intracellular compartments w diff functions
describe the plasma membrane role
- selective barrier that separated a cell form its surroundings
- composed of a phospholipid bilayer embedded w proteins and sometimes carbohydrates
- facilitates intra and extracellular communication through budding and fusing of vesicles in the processes of endo and exocytosis
describe the nucleus
- contains most of the DNA of the cell
- prominent nucleoli may be visible
what encloses the nucleus
- 2 concentric membranes that form the nuclear envelope
- perforated by nuclear pores
what happens when DNA and protein combine
forms chromatin
describe the mitochondria
- harnesses energy from food molecules to produce ATP
what encloses the mitochondria
- 2 membranes: smooth outer and highly convoluted inner
describe DNA in mitochondria
- mitochondria have their own DNA
- reproduce by dividing
describe chloroplasts
- large, green organelles found in plants and lagae
- capture energy from sunlight
what encloses chloroplasts
- 2 membranes
- also possess internal stacks of membranes containing chlorophyll
describe DNA in chloroplasts
- contain their own DNA
- reproduce by dividing
describe endoplasmic reticulum
- irregular maze of interconnected spaces enclosed within a membrane that is continuous with the nuclear envelope
- involved in the production of many cell components
describe rough ER
- studded with ribosomes
- translate RNA into protein
describe smooth ER
- no ribosomes
- involved in the synthesis/ storage of lipids
what is the golgi apparatus
- comprised of stacks of flattened membrane-enclosed sacs
- typically located near the nucleus
- modified and packages molecules made in the ER that are to be secreted or transported to another cell compartment
what is the cytosol
- part of the cytoplasm not containing within intracellular membranes
- very crowded with molecules
how does the cytosol behave
like a water-based gel
what is the difference between cytoplasm and cytosol
- cytoplasm everything in the cell
- cytosol the “empty space” around the other organelles
what does the cytoskeleton do
- governs internal organization
- strength
- shape
- movement
what is the cytoskeleton made up of
protein filaments (anchored across the cell)
what are the primary kinds of cytoskeleton
- actin filaments muscle contraction
- microtubules helps during cell division
- intermediate cell structure and strength
what came first: RNA or DNA
RNA
if RNA came first, what are two things that RNA must be able to do
- store genetic info
- facilitate its own replication via catalytic properties
what about the central dogma confused researchers, and what was the solution
- AA were needed to form proteins, but proteins were needed to form AA
- one needed to be there before the other in order to create the other
- solution must have been autocatalytic
what does autocatalytic mean
feeds into itself
describe the RNA world hypothesis as it evolved to where we are now
- initially autocatalytic RNA only forming itself
- RNA then begins to direct protein synthesis
- DNA then takes over as genetic material, RNA becomes an intermediate between DNA and protein
what is the endosymbiont theory
- explains the origin of eukaryotic cells
- eukaryotes might have originated as a predator that ate other cells
- suggests that mitochondria and chloroplasts were eaten by a eukaryote and thats how they become special organelles
what characteristics of mitochondria support the endosymbiont theory
- own DNA (circular)
- double membranes
- self-replicating
what are used too study life’s common heritage and how
- genomic comparisons
- can use this info to relate one biological system to another
what are some key features of a model system
- reproduce rapidly
- convenient for genetic manipulation
- easy to handle in a lab setting
why do we use e. coli as a model organism
- understand the working more thoroughly than any other living organism
- lives in the gut of humans and other vertebrates, but also grows happily and rapidly in a culture bottle
- we’ve learnt a lot about genes and DNA from them
why do we use yeast as a model system
- is a simple eukaryote (we are eukaryotes too)
- easy and cheap to keep and reprodues rapidly
- reproduces almost as rapidly as bacteria, but is a eukaryote
- taught us a lot about cell division
why do we use arabidopsis as a model system
- can be grown indoors in large numbers
- one plant can produce thousands of offspring in 8-10 weeks
- taught us a lot about the physiology of crop plants that our lives depend on
why do we study caenorhabditis elegans as a model system
- a worm that attacks roots of crops
- develops with clockwork precision, and always has exactly 959 body cells
- has an incredibly precise minute by minute understanding of how they develop
why do we study drosophila melanogaster as a model system
- shows us how genetic instructions in DNA direct zygote development
- d. melanogaster mutants with odd patterns or limbs give the key to identifying genes that are needed for a proper body
- these genes are very similar to those of humans
why do we study d rerio as a model system
- they are transparent for the first two weeks of their life
- provides an idea system to observe how cells behave during development in a living animal
what is another name for d rerio
zebrafish
