BIO 1107

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

1. Transport

2. Enzymatic activity

3. Signal transduction

4. Cell-cell recognition

5. Intercellular joining

6. 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