Module 2 (BIOLOGY) Flashcards
What are the key differences between prokaryotes and eukaryotes?
Nucleus: Absent in prokaryotes (nucleoid region), present in eukaryotes
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Transcription location: Cytoplasm in prokaryotes, nucleus in eukaryotes
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Translation location: Cytoplasm in both
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Cell membrane additions: Hopanoids in prokaryotes, sterols (cholesterol) in eukaryotes
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Size: Smaller in prokaryotes (1−2 micrometers), larger in eukaryotes (10−20 micrometers)
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Ratio of surface area to volume: High in prokaryotes, low in eukaryotes
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Internal organization: No organelles in prokaryotes (some contain plasmids), organelles present in eukaryotes
: What is the cell theory?
All organisms are made up of cells.
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The cell is the fundamental unit of life.
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Cells come from preexisting cells
Front: What are cell membranes composed of?
Lipids, proteins, and carbohydrates
What is the endomembrane system?
An interconnected system of membranes that includes the nuclear envelope, endoplasmic reticulum, Golgi apparatus, lysosomes, vesicles, and plasma membrane
What is the role of mitochondria and chloroplasts?
They are organelles involved in harnessing energy and likely evolved from free-living prokaryotes.
What are phospholipids?
Amphipathic molecules with a hydrophilic head and hydrophobic tails that spontaneously form bilayers.
What are liposomes?
Enclosed bilayers spontaneously formed by phospholipids
What is the function of cholesterol in animal cell membranes?
It acts as a buffer to lessen the impact of temperature changes.
What are the three main types of proteins in the membrane and their functions?
Receptors: Allow the cell to receive signals from the environment.
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Enzymes: Catalyze chemical reactions.
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Transporters: Move ions or molecules across the membrane
What is the difference between integral and peripheral membrane proteins?
Integral membrane proteins: Permanently associated with cell membranes.
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Peripheral membrane proteins: Temporarily associated with the lipid bilayer or integral membrane proteins through weak noncovalent interactions
What is passive transport?
The simplest movement into and out of cells, which does not require energy
hat is the difference between simple diffusion and facilitated diffusion?
Simple diffusion is the movement of molecules across a membrane from an area of high concentration to an area of low concentration. Facilitated diffusion is similar, but the molecules move through a transport protein.
What is osmosis?
The diffusion of water across a semi-permeable membrane from a region of higher water concentration to a region of lower water concentration
What is turgor pressure?
The force exerted by water pressing against an object
What is the difference between passive and active transport?
Passive Transport: Movement of molecules across a membrane that does not require energy.
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Active Transport: Movement of molecules across a membrane that requires energy.
What is secondary active transport?
A type of active transport that uses the energy from the movement of one molecule down its concentration gradient to drive the movement of another molecule against its concentration gradient.
What is an example of primary active transport?
The sodium/potassium pump, which moves sodium and potassium ions in opposite directions across the cell membrane.
What are exocytosis and endocytosis?
Exocytosis: A vesicle fuses with the plasma membrane to deliver its contents outside the cell.
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Endocytosis: Material from outside the cell is brought into a vesicle
What are the functions of the Golgi apparatus?
Further modifies proteins and lipids produced in the ER.
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Sorts proteins and lipids as they move to their final destinations.
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Synthesizes the cell’s carbohydrates.
What is the function of lysosomes?
They degrade proteins, nucleic acids, lipids, and complex carbohydrates
What are the two main types of metabolism?
Catabolism: The breakdown of complex molecules into simpler ones, releasing energy.
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Anabolism: The synthesis of complex molecules from simpler ones, requiring energy.
What is an enzyme?
A biological catalyst that speeds up the rate of a chemical reaction without being consumed in the process.
What is cellular respiration?
The process by which cells convert glucose and oxygen into ATP, the cell’s primary energy currency.
What is photosynthesis?
The process by which plants and other organisms use sunlight to synthesize glucose from carbon dioxide and water.