4 - Cells Flashcards
What is the difference b/w prokaryotes and eukaryotes?
prokaryotes (no nuclear membrane, DNA is circular, no membrane-enclosed organelles, and cell walls usually contain peptidoglycan)
eukaryotes (DNA is enclosed in a membrane bound nucleus and membrane-enclosed organelles)
What are the three shapes of bacteria?
- cocci (spheres)
- bacilli (rods)
- spirillus (spirals)
What are the 4 arrangements of cocci?
round
1. diplo = 2
2. strepto = chain
3. tetrad = 4 (sarcina=8)
4. staphylo = cluster
What are the 2 arrangements of bacillus?
rod
1. diplo=2
2. strepto= chain
What are the 3 arrangements of spirillus?
1+ twists
1. vibrios = curved rods
2. spirilla = corkscrew & rigid
3. spirochetes = helical & flexible
Glycocalyx
“sugar coat” gelatinous substance surrounding cell that is made up of sugar and protein and aids in biofilm development
What are the two types of glycocalyx?
- capsule (firmly attached)
- slime layer (loosely attached)
Axial filaments
mode of movement for spirochetes - fibril bundles at ends of cell - spiral and rotate around cell causing spirochete to move in spiral motion
Flagella
long filament appendages used for movement
What are the 2 major arrangements of flagella?
- petrichous (all over cell)
- polar (at one or both ends of a cell)
What are the 3 major types of polar flagella?
- monotrichous - 1 flagella at 1 pole
- lophotrichous - group of flagella at 1 pole
- amphitrichous - both poles
List the 3 parts of a flagella:
- filament: long, outermost region (made of flagellin)
- hook: attaches filament
- basal body: anchors flagella to cell wall
What is the difference between GRAM + and GRAM - flagella?
Gram - have 2 pairs of rings and Gram + have 1 set of rings
Fimbriae
similar to cilia in eukaryotes - short hairlike appendages for attachment and transfer of DNA (at poles or around entire cell)
Pili
longer than fibriae - motility and DNA transfer (sex pili transfer DNA from one cell to another)
What is the bacteria cell wall made up of?
peptidoglycan
List the sugars in peptidoglycan
repeating disaccharides & polypeptides
1. NAG
2. NAM
Cell walls of gram positive cells
- many thick peptidoglycan layers
- thick rigid cell wall
- teichoic acids
Cell walls of gram negative cells
- thin layer of peptidoglycan
- no teichoic acid
- extra plasma membrane
- outer membrane: lipopolysaccharide (LPS)
Active transport
requires energy low to high concentration
Passive transport
no energy required high to low concentration
What happens when a cell is hypertonic?
shrink - plasmolysis (solute concentration of medium is higher than inside cell)
What happens when a cell is hypotonic?
osmotic lysis (solute concentration of medium is lower than inside cell)
What happens when a cell is isotonic?
equilibrium (equal solute concentration in and out of cell)
Cytoplasm of bacteria
substance inside the cell (water, sugar, lipids, ions, proteins, nucleoid, ribosomes, inclusions)
DNA structure in prokaryotes
- nucleoid (single long circular double strand of DNA with no nuclear envelope/histones)
- plasmids (small circular DNA molecules that are independent of chromosomes and not crucial for survival)
Difference of ribosomes in prokaryotes and eukaryotes, why is this important?
the only difference is size (70s vs 80s) and is important for making antibiotics
Inclusion bodies
accumulate nutrients when abundant/reserve deposits
Endospores
resting cells for survival of extreme conditions - contain DNA, RNA, ribosomes, enzymes - only Gram +
Nucleus of eukaryotes
membrane bound-nuclear envelope that contains DNA with histones that are organized into chromosomes and have a nucleolus at the center where rRNA is made
Rough ER
folds and processes proteins (has ribosomes)
Smooth ER
makes phospholipids, fats, sterols
Golgi complex
protein packaging and transport (post-office of the cell)
Lysosomes
digestive center
Mitochondria
produces the energy for the cell (ATP) made up of two membranes (cristae: sack-like folds and matrix: inside of mitochondria)
Chloroplasts
photosynthesis in algae and plants - sunlight converted to energy
taxis
movement toward or away specific stimuli
Two types of taxis
- chemotaxis: toward/away from chemicals
- phototaxis: toward/away from light
What color is gram positive/negative?
+ : purple
- : red
How does penicillin work?
interferes with formation of peptidoglycan (gram + susceptible)
What are the 3 parts of the LPS?
- Lipid A - endotoxin
- Core polysaccharide - structure and stability
- O polysaccharide - sugar that extends out
Diffusion
movement of molecules from high to low concentration that requires no energy
Facilitated diffusion:
proteins act as channels to help move molecules across membrane - no energy required (high to low)
Osmosis
diffusion of water from high to low or low to high solute concentration
What is the mobility difference between flagella of prokaryotes and eukaryotes?
eukaryotes move wavelike and prokaryotes spin
What makes up the cell wall of algae and plants?
cellulose
What is the major difference between the prokaryote and eukaryote cytoplasm?
eukaryotes have a cytoskeleton
What is endocytosis?
uptake of material from outside the cell
What are the two types of endocytosis?
- phagocytosis: plasma membrane surrounds molecule and engulfs it
- pinocytosis: cell brings fluid into cytoplasm
