January 1, 20XX
In one recorded patrol against allied enemies' alliances, Mario and Sonic gathered with their allies – Luigi, Yoshi, Tails, Knuckles, Amy, and others – united against a common threat. Bowser, fueled by newfound alliances, had teamed up with Dr. Robotnik to deploy a formidable regiment of Koopas and Eggbots. The iconic heroes, ever ready for adventure, stood side by side, determined to thwart this menacing alliance.
As the horizon darkened, Bowser's Koopas marched forward with Eggman's robots clanking alongside. Mario, clad in his red cap and blue overalls, took the lead, shouting orders to his allies. Sonic, his blue fur glistening in the fading sunlight, cracked a confident grin.
The battlefield erupted into chaos as Mario and Sonic's team clashed with the patrolling forces. Yoshi, with Mario riding on his back, darted through the chaos, swallowing Koopas whole and delivering swift kicks to the advancing robots. Meanwhile, Tails soared through the air, unleashing technological prowess to disable Eggman's contraptions.
Luigi, armed with his paranormal expertise, faced off against Koopas with an array of ghostly powers. Knuckles, the guardian echidna, used his powerful fists to punch through the metallic defenses of Eggman's Robots. Amy, wielding her giant hammer, gracefully danced through the chaos, taking down enemies with precision.
In the midst of battle, Sonic dashed around the field, creating a whirlwind of speed that left Koopas and Eggbots disoriented. Mario, displaying his signature jumping prowess, smacked out one of Bowser's leading officers, ready to confront any more challenges.
As the clash intensified, Bowser and Dr. Robotnik monitored the situation from the safety of their flying contraptions.
Bio Notes: (filled with academic musings)
All cell types share 4 fundamental cell components
1) An enclosing plasma membrane which separates the cell's interior from the environment
2) Cytoplasm made of cytosol in which other components of the cell are found
3) DNA - the genetic material of the cell
4) Ribosomes which synthesize proteins
Cell type dictates the cell structure
Two categories of Cells:
Prokaryotic cells — Bacteria and Archaea
Eukaryotic cells — plants, fungi, protists, and animals
• Chromosomal DNA is localized in a nucleoid
• Ribosomes are in the cytoplasm
• The cell membrane is surrounded by a cell wall
• The other structures shown may be present in some, but not all, bacteria
Prokaryotes are mostly single celled organisms lacking internal organelles
Prokaryotic cells are smaller than eukaryotic cells
Reasons for small size of prokaryotic cells:
– Surface area to volume ratio is more favorable for moving material in and out of the cell
– They lack modifications found in eukaryotes that aid internal transport
Factors Limiting Cell Size
Surface area–to–volume ratio
– As cells get bigger, volume increases faster than surface area
Eukaryotic Cells
The plasma membrane is a mosaic model of lipids and proteins
Outside of cell
Hydrophilic region of protein
Hydrophilic head
Hydrophobic tail
Hydrophobic regions of protein
Phospholipid bilayer
Cytoplasm (inside of cell)
Cell wall not present in animal cells
Plant Cell
Animal Cell
Animal Cell Membrane
Eukaryotic plasma membrane
Phospholipid bilayer with embedded proteins.
ACE2: (Angiotensin-Converting Enzyme 2)
Helps to control blood pressure in the lungs by dilating the blood vessels
Cytoplasm: Region between the plasma membrane and the nuclear envelope
• This consists of organelles suspended in gel-like cytosol plus the cytoskeleton.
• 70-80% of the cytoplasm is water but it has semi-solid consistency due to proteins within it.
Nucleus
• Usually only one per cell – the largest organelle (10% of cellular contents) – Bigger itself than most prokaryotic cells
Nuclear Envelope is a double membrane structure and forms the outermost portion of the nucleus
• Double membrane – Separates DNA from cytoplasm – Separates transcription from translation
• Nuclear pores perforate this membrane – Connect nucleoplasm to cytoplasm – Regulate flow of molecules back & forth – Large molecules require nuclear localization signal (NLS) to pass
THE NUCLEUS HOLD THE HEREDITARY INFORMATION OF THE CELL, THE DNA
Nucleolus is the region inside the nucleus where ribosomes are assembled from RNA and proteins
Ribosomes are the cellular structures responsible for protein synthesis - Translation
• Made of two different-sized subunits
• Slightly larger in eukaryotes
• Made of special RNA (rRNA) and proteins
• During protein synthesis, ribosomes assemble amino acids into proteins
Mitochondrion is the powerhouse of the cell
• Site for conversion of stored energy (macromolecule molecular bonds) to more useful form (ATP)
• Inner membrane is folded – Folds are called cristae – Area enclosed is the mitochondrial matrix
Electron micrograph of a mitochondrion
Peroxisomes
• Peroxisomes are small rounded organelles enclosed by a single membrane
• Reactions that break down fatty acids and amino acids
• Peroxisomes may detoxify poisons
Contrasting Animal and Plant Cells
• Both have microtubule organizing centers (MTOCs), but animal cells also have centrioles associated with the MTOC
– This complex is called the centrosome
• Animal cells each have a centrosome and lysosomes but plant cells do not
• Plant cells have a cell wall, chloroplasts and other specialized plastids and a large central vacuole - animal cells do not
Channels between cells
Not in most plant cells
Central vacuole
Cell wall
Chloroplast
Not in animal cells
Centrosome
• The centrosome consists of two centrioles that lie at right angles to each other
• Each centriole is a cylinder made up of nine triplets of microtubules
• Nontubulin proteins (indicated by the green lines) hold the microtubule triplets together
Lysosomes
• Lysosomes in animal cells contain digestive enzymes, the cells "garbage disposal"
• These breakdown large biomolecules and even worn-out organelles
Lysosome
Plant Cell Walls
• The cell wall is a rigid protective structure external to the plasma membrane
• Plant cell walls differ from prokaryotes because they are made up of cellulose rather than peptidoglycan.
Cellulose molecule
Chloroplasts
• Chloroplasts are double-membrane organelles; have
their own ribosomes and DNA like mitochondria
• The inner membrane encloses an aqueous fluid (stroma) that contains a set of interconnected and stacked fluid-filled membrane sacs called thylakoids
• Each stack of thylakoids is a granum (plural = grana).
The Central Vacuole
• Plant cells have a large vacuole that occupies most of the area of the cell
• This central vacuole helps regulate water concentration under changing environmental conditions, and contributes to cell expansion