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Light Microscope
An optical instrument with lenses that refract (bend) visible light to magnify images of specimens.
Magnification
the ratio of an object's image size to its real size.
Resolution
measure of clarity ofthe image, or the minimum distancebetween two distinguishable points.
Contrast
difference in brightness between light and dark areas of image.
Scanning Electron Microscopes
focus a beam of electrons onto surface of specimen producing 3D images.
Transmission Electron Microscopes
focus a beam of electrons through a specimen
Fundamental Unit of Life
Cells are the simplest collection of matter that can be alive.
prokaryotic cell
A type of cell lacking a membrane-enclosed nucleus and membrane-enclosed organelles; found only in the domains Bacteria and Archaea.
Eukaryotic cells
Contain a nucleus and other organelles that are bound by membranes.
plasma membrane (cell membrane)
A selectively-permeable phospholipid bilayer forming the boundary of the cells
Cytosol
Fluid portion of cytoplasm
Cytoplasm
A jellylike fluid inside the cell in which the organelles are suspended
Chromosomes
carry genes in the form of DNA
Ribosomes
Makes proteins
Prokaryotic vs. Eukaryotic
Eukaryotic cells have nucleus and membrane bound organelles. Prokaryotic cells (BACTERIA) are unorganized and don't have a nucleus
Hydrophobic
Water fearing
hydrophillic
water loving
amphipathic
having both a hydrophilic region and a hydrophobic region
metabolic requirements
set upper limits on the size of cells
As cell size increases
surface are increases proportional to the square of linear dimension
Volume increases
proportional to the cube of linear dimension
Animal cell organelles
cell membrane, centrosome, cytoplasm, rough ER, smooth ER, ribosomes, golgi body, mitochondrion, vacuole, nuclear membrane, nucleolus, nucleus, lysosome
Centrosome
A structure in animal cells containing centrioles from which the spindle fibers develop.
Endoplasmic Reticulum
A cell structure that forms a maze of passageways in which proteins and other materials are carried from one part of the cell to another.
Nucleus
A part of the cell containing DNA and RNA and responsible for growth and reproduction
Microvilli
Fingerlike extensions of plasma membrane of apical epithelial cells, increase surface area, aid in absorbtion, exist on every moist epithelia, but most dense in small intestine and kidney
Microfilaments
Long, thin fibers that function in the movement and support of the cell
intermediate filaments
Threadlike proteins in the cell's cytoskeleton that are roughly twice as thick as microfilaments
Microtubules
Spiral strands of protein molecules that form a tubelike structure
cell wall
A rigid layer of nonliving material that surrounds the cells of plants and some other organisms.
Peroxisomes
Contain oxidase enzymes that detoxify alcohol, hydrogen peroxide, and other harmful chemicals
Lysosomes
An organelle containing digestive enzymes
Chloroplast
An organelle found in plant and algae cells where photosynthesis occurs
Vacuole
a space or vesicle within the cytoplasm of a cell, enclosed by a membrane and typically containing fluid.
Chromatin
DNA & proteins of chromosomes together
Nucleolus
Found inside the nucleus and produces ribosomes
endomembrane system
A network of membranes inside and around a eukaryotic cell, related either through direct physical contact or by the transfer of membranous vesicles.
Smooth ER
That portion of the endoplasmic reticulum that is free of ribosomes.
Synthesizes lipids (oils, steroids, & membrane phospholipids)
Metabolized carbohydrates
Detoxifies drugs and poisons
Stores calcium ions
Golgi apparatus
A system of membranes that modifies and packages proteins for export by the cell
endosymbiotic theory
theory that eukaryotic cells formed from a symbiosis among several different prokaryotic organisms
Mitochondria
Powerhouse of the cell
Cytoskeleton from smallest to largest
microfilaments, intermediate filaments, microtubules
cell junctions
contact points between the plasma membranes of tissue cells
tight junctions, Anchoring Junctions (desmosomes), gap junctions
3 types of cell junctions
tight junctions
Membranes of neighboring cells are pressed together, preventing leakage of extracellular fluid
anchoring junctions
fasten cells together into sheets
gap junctions
provide cytoplasmic channels between adjacent animal cells
selective permeability
A property of a plasma membrane that allows some substances to cross more easily than others.
fluid mosaic model
model that describes the arrangement and movement of the molecules that make up a cell membrane
cholesterol and membrane fluidity
-at low temperatures, cholesterol interferes with the crystal structure of the cell membrane and occupies space between phospholipid molecules → increases fluidity
-at high temperatures, it restricts excessive movement of phospholipids → decreases fluidity
integral proteins
penetrate the hydrophobic interior of the lipid bilayer
peripheral proteins
loosely bound to the surface of the membrane
Six major functions of membrane proteins
Transport
Enzymatic activity
Signal transduction
Cell-cell recognition
Intercellular joining
Attachment to the cytoskeleton and extracellular matrix (ECM)
membrane carbohydrates
interact with the surface molecules of other cells, facilitating cell-cell recognition
permeability of membrane
Nonpolar molecules-hydrocarbons, CO2, O are hydrophobic and can pass through the membrane easily
Hydrophobic core of the membrane prevents the passage of ions and polar molecules (are hydrophilic), big molecules difficult
Hydrophilic substances avoid the lipid bilayers by passing through transport proteins
passive transport
the movement of substances across a cell membrane without the use of energy by the cell
Diffusion
Movement of molecules from an area of higher concentration to an area of lower concentration.
facillitated diffusion
when transport proteins make room for larger substances to pass through cell membrane
Osmosis
Diffusion of water through a selectively permeable membrane
active transport
Energy-requiring process that moves material across a cell membrane against a concentration difference
Hypotonic
Having a lower concentration of solute than another solution
Hypertonic
when comparing two solutions, the solution with the greater concentration of solutes
sodium-potassium pump
a carrier protein that uses ATP to actively transport sodium ions out of a cell and potassium ions into the cell
Exocytosis
Process by which a cell releases large amounts of material
Endocyosis
the process during which a cell takes in a substance by surrounding it with the cell membrane
Metabolism
All of the chemical reactions that occur within an organism
Bioenergetics
the study of how energy flows through living organisms
metabolic pathway
A series of chemical reactions that either builds a complex molecule or breaks down a complex molecule into simpler compounds.
Catabolic Pathway
A metabolic pathway that releases energy by breaking down complex molecules to simpler compounds.
anabolic pathways
Metabolic pathways that consume energy to build complicated molecules from simpler ones.
Energy
the ability to do work
work
is movement of matter againstopposing forces
first law of thermodynamics
Energy can be transferred and transformed, but it cannot be created or destroyed.
kinetic energy
energy of motion
potential energy
stored energy
chemical energy
Energy stored in chemical bonds
second law of thermodynamics
Every energy transfer or transformation increases the entropy of the universe.
Entropy
A measure of disorder or randomness.
free energy
energy that is available to do work
change in free energy
𝛥G
changes in this provide information about the chemical reactions and can predict whether a chemical reaction is favorable and will occur
this will predict what direction the chemical reaction will go spontaneously
predicts changes occurring at any concentration of products and reactants and at any temperature
