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Bio principles Exam 2 – Brooks Latest
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Cytology ✔✔the study of cells
Robert Hooke ✔✔- observed cork could float
- discovered a honeycomb-like structure in a cork slice using a primitive compound microscope
- only saw cell walls as this was dead tissue
- coined the term "cell" for these individual compartments he saw
Two types of microscopes: ✔✔1. Light Microscope
- Electron Microscope
Light Microscope ✔✔- light is focused on specimen by a glass condenser lens
- the image is magnified by an objective lens and an ocular lens
- projection on photographic film
Electron Microscope ✔✔- a beam of electrons is used instead of light
- bombards object with electrons to see small, precise images
- electromagnets are used instead of glass lenses
- the electron beam is focused on the specimen by a condenser lens
- the image is magnified by an objective lens and projector lens
- projection on a screen or on photographic film
Two Types:
- Transmission Electron Microscope
- Scanning Electron Microscope
Transmission Electron Microscope (TEM) ✔✔- magnet lens focus on electron beam
- the image can be viewed through a viewing lens
- cuts thin slices with a microtome made of diamonds
- displays different colors depending on electrons absorbed
Scanning Electron Microscope (SEM) ✔✔- a scanning coil moves the beam back and forth
- electrons reflected from the specimen are analyzed by a computer to reconstruct a 3D image
- composed of carbohydrates (cellulose = plants, chitin = fungi) or carbohydrate derivative (peptidoglycan = bacteria)
Cytoplasm ✔✔- material outside the nucleus
- site for metabolic activity
- contains cytosol (intracellular fluid)
- organelles
Cytosol ✔✔solution with dissolved substances with specialized functions; the intercellular fluid in the cytoplasm
Organelles ✔✔membrane-bound subunits of cells with specialized functions
Cytoskeleton ✔✔supportive by maintaining cell shape and metabolic structure composed of microtubules, microfilaments and intermediate filaments
Microtubules ✔✔- Spiral strands of protein molecules that form a tubelike structure within the cell's cytoskeleton
- form cilia (short & numerous), flagella (long & few) and centrioles → all for locomotion
Microfilaments ✔✔Fine, threadlike proteins found in the cell's cytoskeleton
example: actin (protein)
Intermediate Filaments ✔✔Threadlike proteins in the cell's cytoskeleton that are roughly twice as thick as microfilaments
Prokaryotic Cells ✔✔- nucleoid (no nucleus) with DNA in continuous loop
- no membrane bound organelles
- simple cellular organization
- flagella rotate
- ribosomes present
- plasma membrane produces ATP
- cell wall
Eukaryotic Cells ✔✔- membrane bound organelles
- complex cellular organization
Golgi Apparatus ✔✔- packaging center for molecules
Lysosomes ✔✔- hydrolytic enzymes for intracellular digestion
Peroxisomes ✔✔- H₂O₂ (hydrogen peroxide) synthesis and degradation
Chloroplast ✔✔- site for photosynthesis
(cyanobacteria gave rise to chloroplasts in plants)
Chromoplast ✔✔- contains non green pigments
Ex: Carotenoid
Leukoplast ✔✔- stores starch
Mitochondrion ✔✔- ATP synthesis
- powerhouse of cell
- aerobic
- breaks down fuel molecules and capturing energy in cellular respiration
Vacuole ✔✔- storage and space filling structure
Mitochondrion and Chloroplast are ✔✔evolutionary aspects.
Plasma Membrane "Fluid Mosaic Model" ✔✔- phospholipids
- glycoproteins
- proteins
- cholesterol
Phospholipid ✔✔composed of a phosphate head and fatty acid tail
Categories of Passive Transport ✔✔1. Simple Diffusion
- Facilitated Diffusion
- Osmosis
- Bulk Flow
Simple Diffusion ✔✔- movement from an area of high concentration to an area of low concentration
- no membrane required
- all particles in motion rely on heat and thermal energy
Ex: sugar dissolving in water
Facilitated Diffusion ✔✔a permease, or membrane enzyme, carries a substance (membrane facilitates movement)
- channel proteins
- carrier proteins
Osmosis ✔✔diffusion across a semi-permeable membrane; hypotonic to hypertonic
- osmotic pressure
- turgor pressure
Osmotic Pressure ✔✔pressure required to prevent diffusion from a pure solvent into the solution across a semi-permeable membrane
Turgor Pressure ✔✔the force within the cell that pushes the plasma membrane against the cell wall
- wilting = plasmolysis (vacuous and cell sap)
Tonicity ✔✔the relative concentration of solutes
T/F When comparing two or more solutions, the solute levels can be equal (i.e., isotonic for both) or unequal (i.e., one is hypertonic to the other, which is hypotonic) ✔✔True
A hypotonic solution has _______ water per volume than a hypertonic solution. ✔✔more
Shriveled ✔✔- animal cell
- cell shriveled
- hypertonic solution
Turgid (normal) ✔✔- plant cell
Flaccid ✔✔- plant cell
Plasmolyzed ✔✔- plant cell
Crenation ✔✔plasmolysis (contraction of the protoplast of a plant cell as a result of loss of water from the cell)
What happens to a plant cell when placed in distilled water? ✔✔Cells come turgid (cell stiffens but retains shape)
What happens to a plant cell when placed in concentrated salt solution? ✔✔Cells become plasmolyzed (cell body shrinks and pulls away from cell)
Plant cells prefer ✔✔hypotonicity (wants to fill vacuole).
Cytolysis ✔✔hemolysis (rupture or destruction of red blood cell)
What happens to red blood cell when placed in distilled water? ✔✔Cells lyse (swell and burst)
What happens to a red blood cell when placed in concentrated salt solution? ✔✔Cells shrivel (shrink and shrivel)
Animal cells prefer ✔✔isotonicity.
Bag (98% water, 2% sucrose) placed in: ✔✔- 100% distilled water = hypotonic (water diffuses into bag, cells swell up/lyse)
- 90% distilled water, 10% sucrose = hypertonic (water diffuses out of bag, cells shrink/shrivel)
- Since the water coming into the mouths of saltwater fish is hypertonic, they send some of it down through their digestive tract, the same way humans drink (and the rest goes over the gills). Seawater fish do drink water.
Would a swimmer lose or gain minute amounts of water weight after extended periods in a freshwater pool? ✔✔you will gain weight because the water is hypotonic compared to our body.
Would a swimmer lose or gain minute amounts of water weight after extended periods in saltwater? ✔✔you will lose weight because the water is hypertonic compared to our body.
Explain why excess salt (NaCl) in our diets can easily lead to high blood pressure. ✔✔- blood in blood vessels increase due to the absorption of water from tissues and the shriveling of cells
- water increases volume of vessels creating high pressure
Explain why a stranded, dehydrated boater out in the Atlantic Ocean --- without any freshwater on the boat --- cannot safely drink the saltwater. ✔✔The salt concentration of the ocean water would cause dehydration. The body of the stranded boater would become hypertonic compared to the ocean if the salt water was consumed, leading to shriveling and shrinking of the cells as water leaves the body.
Explain why a person could die from drinking too much freshwater, aka water intoxication. ✔✔
Describe why the following definition of osmosis is actually correct: Movement of water across a semipermeable membrane from the hypotonic to the hypertonic environment. ✔✔When osmosis occurs, the movement of water goes from a hypotonic to hypertonic environment. The solute concentration is initially lower and gradually increases to a higher solute concentration.
Which of the following would best describe 50% solvent and 50% solute? ✔✔50% solution
T/F Wherever you have more solute, water will flow. ✔✔True. Solute attracts water (solvent).
Active Transport ✔✔relies on the cell to provide the energy supply to move materials
- via cell supplying energy/ATP (usually goes against the concentration gradient)
Bulk Flow ✔✔mass movements of fluids affected by pressure and solutes
Categories of Active Transport ✔✔1. Membrane Pumps (Na/K exchange pump)
- Endocytosis
Difference between heat and temperature: ✔✔The ocean has a higher heat, while the body has a higher temperature.
Cell Connections in Plants: ✔✔- plasmodesma
Cell Connections in Animals: ✔✔- tight junctions (ex: urinary bladder)
- gap junctions (ex: cardiac muscle)
- desmosomes (ex: fiber desmosomes are flexible and allows for stretching)
Energy ✔✔- can be generally categorized to its passive or active state
- is required by all forms of life to become and remain organized - which requires work!
- comes in many specific forms, but can generally be categorized as energy that "IS" doing work (Kinetic) and energy that "COULD" do work (Potential).
The total energy in a system must always be accounted for, but when potential energy is used to do work UNFORTUNATELY most of the energy will be wasted as _____ ✔✔heat.
Kinetic Energy (KE) ✔✔KE = ½ mv²
- exists whenever an object which has mass is in motion with some velocity
- is in action or actively doing work
Example: everything you see moving
KE forms: ✔✔electrical, light (radiant), heat (thermal), movement
Potential Energy (PE) ✔✔PE = mgh
- exists whenever an object which has mass has a position within the forcefield
- is stored for subsequent use to do work
Example: the position of objects in the earth's gravitational field
Potential Energy = free energy
Greater height = greater PE
