Cells Flashcards
cell
basic unit of life
cell theory (1850s)
says cells = basic living units of organization/function in all organisms
all cells come from other cells
organelles
parts w/in a cell
used for energy conversion & synthesis
composed of biomacromolecules
biomacromolecules
proteins, lipids, carbs, nucleic acids
plasma membrane
surrounds all cells
regulates passage of materials in/out of cells via “pumps” & “gates”
surface area-volume ratio
as a cell expands, its SA relative to V decreases
larger SA/V ratio –> faster metabolic processes (that’s why cells stay small)
2 basic types of cells
- prokaryotic (simple)
2. eukaryotic (complex)
prokaryotic cells
- smaller
- DNA not enclosed in a nucleur membrane (“prokaryotic” = before the nucleus)
- don’t contain many of the internal membrane bound organelles that are found in eukaryotic cells
- ex. = botulism (bacteria)
contents of prokaryotic cells
- plasma membrane (often folded inward to create folds for metabolic processes)
- ribosomes (made of RNA) that synthesize proteins for cell to use
eukaryotic cells
- complex
- 10-100x larger than prokaryotic cells
- contain true nucleus (w/nuclear membrane)
- many membrane-bound organelles
nucleus
contains DNA, control center of cell, surrounded by nuclear membrain
DNA
sequences of nucleotides in the form of chromosomes
genes
specific sections of chromosomes that determine what proteins are synthesize by ribosomes
ribosomes
- tiny manufacturing plants, resemble proteins
- contain ribosomal RNA & enzymes (which form the peptide bonds btwn amino acids)
- assemble amino acids in an order determined by DNA (communicated by mRNA)
mRNA
messenger RNA
brings info from DNA to the ribosomes to tell them how to assemble the amino acid chains for each protein
endoplasmic reticulum (ER)
- extension of nucleus’ outer membrane
- maze of tightly packed, flattened sac-like structures
- “rough” ER & “smooth ER”
rough ER
where ribosomes are located
modifies and transports proteins produced by ribosomes
smooth ER
no ribosomes, where lipids are synthesized
FYI: liver cells have a huge smooth ER bc that’s where cholesterol is formed
cytoplasm
- fluid portion of cell
- contains all organelles outside of nucleus
golgi complex
- made up of stack of flattened sacs (“cisternae”)
- receives the lipids & proteins that were synthesized in the ER, alters their structures, and ships them off to other parts of cell
- produces lysosomes
vesicles
vessels that carry lipids/proteins to other parts of cell by fusing through membrane
lysosomes
- small sacs of digestive enzymes
- breakdown biomacromolecules into monomers (building blocks) that are recycled to build new biomacromolecules
- can also break down bacteria that enters cell
- FYI: Tay Sachs disease occurs when lysosomes lack the enzyme that breaks down toxic lipids in brain cells
mitochondria
-organelles that convert chemical energy in food –> ATP
via aerobic cellular respiration (which just means that oxygen is needed to break down glucose)
-bound by double membrane (2 membranes + space in middle)
-inner membrane has many folds which increases the surface area for chem. reactions and enzymes to turn food energy into ATP
matrix
center of a mitochondrion
cytoskeleton
- network of protein fibers (microtubules & microfilaments)
- provides cells with structural support & mvmt
microtubules
- hollow cylinders involved in cell division & cilia/flagella (other parts of cell) structure
- anchored to cell via microtubule-organizing centers (MTOCs)
microfilaments
flexible, solid fibers of 2 intertwined polymer chains of actin molecules
centrioles
- 2 located inside each MTOC
- made up of 9 sets of 3 tubules forming a hollow cylinder
cell coat
- part of outside of cell
- made up of polysaccharide side chains that allow cells to recognize each other, make contact, and/or connect
cell wall
NOT in ppl/animal cells!
- in plants: thick cell wall made of layers of cellulose fibers for structural support & mechanical strength
- in bacteria: cell wall often contains peptidolycan (mesh-like structure made of sugars & amino acids). penicillin works by weakening this cell wall
gram positive
- cell wall contains thick layer of peptidoglycan
- this layer will absorb a violet stain
gram negative
- cell wall contains thin layer of peptidoglycan
- this layer will not absorb a violet stain
endospore
dormant, extremely durable cell produced by the bacteria clostridium botulinum which can lead to botulism.
aerobic respiration
eukaryotic cell process of mitochondria converting the chemical energy found in food (glucose) into ATP. oxygen is required to break down glucose, Carbon dioxide, water and ATP are produced.
