Chapter 3 Flashcards
All living things are composed of one or more cells
Modern cell theory
Cells come from other cells
Biogenesis
Provides an explanation for how eukaryotic cells could have arisen from prokaryotic cells
Chloroplasts and mitochondria could be descended from prokaryotes that were engulfed by other cells
Endosymbiotic theory
While prokaryotes don’t have a nucleus, they still have _____?
DNA
The condensed region of DNA within a prokaryotic cell is called the ______?
Nucleiod
Are small circular pieces of extra chromosomal DNA
Carry non essential genes
Often contain genes for antibiotic resistance, adaptability to environmental stressors, toxins
Can be exchanged between bacteria, providing genetic variability within a population
Plasmids
Site of protein synthesis
Are composed of two sub units
Ribosomes
Prokaryotic subunits
Total size
Ribosomes
30s + 50s
Total ribosome size 70s
Members of the genera _______ and ______ are endospore formers
Both of these genera include important human pathogens
Bacillus and clostridium
Sporulation
- DNA replicates
- Membranes form around the DNA
- Fore-spore forms additional membranes
- Protective cortex forms around the spore
- Protein coat forms around the cortex
- Endospore is released
Phospholipid bilayer
Semipermeable membrane
Plasma membrane
Down a concentration gradient
Simple diffusion
Allows solutes to cross the membrane down a concentration gradient
From high to low
A protein channel forms a doorway for the molecule
No energy required
Facilitated diffusion
Movement is against the concentration gradient from low to high
Energy is required ATP
Active transport
Most bacteria have cell walls made of ______?
Chains of disaccharides
Cross linked by peptide bridges
Along with the cytoskeleton, determines the cells shape.
Provides resistance to lysis
Peptidoglycan
Some genera of bacteria have waxy cell walls containing
Mycolic acids
Mycobacterium (tuberculosis)
Nocardia (n. Asteroids)
The cell walls makes the cells resistant to staining
Acid fast cell walls
Some bacteria produces an outer coating of polysaccharide or protein called a
Gycocalyx
Capsules can contribute to ________ by: promoting adherence to tissues, and preventing phagocytosis by white blood cells
Pathogenicity
Short bristle like
Cover the entire cell surface
Aid in attachment
Fimbriae
Longer than fimbriae, less numerous
Used for attachment, exchanging DNA
These genes can be turned on or off depending on the needs of the cell
Pili
Flagellar movement occurs in a series of _______ and _______
Runs and tumbles
Clockwise rotation of flagella
Tumbling
Counter clockwise rotation of flagella
Running
Bacteria can move towards or away from a chemical stimulant such a sugar
Chemotaxis
Bacteria can move toward light
Phototaxis
May be unicellular or multicellular
Eukaryotes
A double membrane within the cell contains
DNA
Nucleoplasma
Eukaryotic cells contain a _______
Eukaryotic chromosomes are _______
Nucleus
Linear
The DNA is wrapped around proteins called
Histones
The ________ is found within the nucleus
Site of rna synthesis and ribosome pre assembly
Nucleolus
Made up of 2 subunits 40s and 60s
Total size 80s
Site of protein synthesis
Membrane bound ribosomes attached to the rough endoplasmic reticulum
Ribosomes
Mitochondria and chloroplasts have _____ ribosomes similar to prokaryotes
70s
A series of flattened membranes sacs near the plasma membrane
Modifies proteins and lipids
Modified molecules are then inserted into the plasma membrane or secreted outside of the cell via Exocytosis
Golgi apparatus
Vesicles containing digestive enzymes
Lysosomes
A series of micro filaments, intermediate filaments, and micro tubules
Provides internal support
Involved in intracellular transport
Cytoskeleton
Site of ATP synthesis in eukaryotic cells
A double membrane surrounding a thick fluid matrix
Inner membrane has folds called cristae
Mitochondria
The plasma membrane invaginates to bring material into the cell
Endocytosis
Produce hydrogen peroxide, catalase, and involved in lipid biosynthesis
Peroxisomes
Similar to the plasma membrane of prokaryotes, contains sterols, cholesterol, ergosterol, affect membrane fluidity
Plasma membrane (eukaryote)
Has ribosomes on its surface and packages proteins for transport in the cell
Rough ER
Lacks ribosomes on its surface; pinches off bubbles of membrane for growth and repair proteins for secretion
Smooth ER
Long membrane extensions that move substances along the surface
Cilia
Are shorter than flagella and cover the surface of the cell
Beat in a wave like fashion
Cilia
Similar to prokaryotic flagella are long and thin
Microtubule arrangement allow for bending
Flagella (eukaryotic)
