105 terms

What is life? A Guide to Biology: Chapter 3 (EXAM #1)


Terms in this set (...)

The smallest unit of life that can function independently and perform all the necessary functions of life, including reproducing itself.
Cell Theory
A unifying and universally accepted theory in biology, that holds that all living organisms are made up of one or more cells, and that all cells arise from other, pre-existing cells.
Eukaryotic cell
A cell with a membrane-bound nucleus containing DNA, membrane-bound organelles, and internal structures organized into compartments.
An organism composed of eukaryotic cells. (good - kernel).
Prokaryotic cell
A cell bound by a plasma membrane enclosing the cell contents (cytoplasm, DNA, and ribosomes); there is no nucleus or other organelles.
An organism consisting of a prokaryotic cell (all prokaryotic cells are one celled organisms).
Plasma membrane
A complex, thin, two-layered membrane that encloses the cytoplasm of the cell, holding the contents in place and regulating what enters and leaves the cell; also called the cell membrane.
The jelly-like fluid that fills the inside of the cell; in eukaryotes, the cytoplasm contains the organelles.
Granular bodies in the cytoplasm, released from their initial positions on the rough endoplasmic reticulum, that copy the information in segments of DNA to provide instructions for the constructions of proteins.
Cell wall
Found in plant cells and provides the cell with structural strength, gives the cell increased water resistance, and provides some protection from insects and other animals that might eat plant parts.
Flagellum (flagella)
Long, thin, whip-like projections from the cell body of q prokaryote that aid in cell movement through the medium in which the organism lives; in animals, the only cell with a flagellum is the sperm cells.
Pili (pilus)
A thin, hair-like projection that helps a prokaryote attach to surfaces.
The largest and most prominent organelle in most eukaryotic cells This organelle has two primary functions: genetic control center and storehouse for hereditary information.
Specialized structures in the cytoplasm of eukaryotic cells with specific functions, such as the rough and smooth endoplasmic reticulum, Golgi apparatus, and mitochondria.
Endosymbiosis Theory
Theory of the origin of eukaryotes that holds that in the past two different types prokaryotes engaged in a close partnership and eventually one, capable of performing photosynthesis, was subsumed into the other , a larger prokaryote; the smaller prokaryote made some of its photosynthesis energy available to the host, and over time the two became symbiotic and eventually a single more complex organism in which the smaller prokaryote had evolved into the chloroplast of the new organism (smaller scenario can be developed for the evolution of mitochondria)
An organelle found in all plants and eukaryotic algae, is the site of photosynthesis, the conversion of light energy into the chemical energy of food molecules, with oxygen as a by-product.
The folding in of a membrane or layer of tissue so that an outer surface becomes in inner surface.
A lipid that is the major component of the plasma membrane; phospholipids are structurally similar to fats, but contain a phosphorus atom and have two, not three, fatty acid chains.
A small molecule that forms the head region of a triglyceride fat molecule.
Having an electrical charge.
Molecules that can mix with water--("water loving") molecules.
Electrically uncharged.
Carbon-hydrogen chains are non-polar molecules because they have no electrical charge and because they are non-polar, these molecules do not mix with water--("water fearing").
Phospholipid bilayer
The structure of the plasma membrane; two layers of phospholipids, arranged tail to tail (the tails are hydrophobic and so avoid contact with water), with the hydrophilic head regions facing the watery extracellular fluid and intracellular fluid.
Transmembrane Proteins
A protein that can penetrate a phospholipid bilayer of a cell's plasma membrane.
Surface proteins
A protein that resides primarily on the inner or outer surface of the phospholipid bilayer which constitutes the plasma membrane of the cell.
Receptor proteins
A protein in the plasma membrane that binds to specific chemicals in the cells external environment to regulate processes within the cell. For example, cells in the heart have receptor proteins that bind to adrenaline.
Recognition proteins
A protein un the plasma membrane that provides a "finger print" on the outside-facing surface of the cell, making it recognizable to other cells; recognition protein make it possible for the immune system to distinguish the body's own cells from invaders that may produce infection, and also help cells bind to other cells or molecules.
Transport proteins
Transport proteins are integral transmembrane proteins; that is they exist permanently within and span the membrane across which they transport substances.
Enzymatic proteins (see enzyme)
A that protein that initiates and accelerates a chemical reaction in a living organism enzymatic proteins take a part in chemical reactions on the inside and outside surfaces of the plasma membrane.
One of the sterols, lipids important in regulating growth and development; cholesterol is an important component of most cell membranes, helping the membrane to maintain its flexibility.
Passive transport in which a particle, called a solute, is dissolved in a gas or liquid (called a solvent) and moves from an area of high solute concentration to an area of lower concentration.
sugar is the solute.
water is the solvent
Simple diffusion
Diffusion of molecules directly through the phospholipid bilayer of the plasma membrane that takes place without the assistance of other molecules; oxygen and carbon dioxide because they are small and carry no charge that would cause them to be repelled by the middle layer of the membrane, can pass through the membrane in this way.
Facilitated Diffusion
Diffusion of molecules directly through the phosphlipid bilayer of the plasma membrane that takes place trough a transport protein (a carrier molecule") embedded in the membrane, molecules that the assistance of a carrier molecule are those that are too big to cross the membrane directly or are electrically charged and would be repelled by the middle layer of the membrane.
A type of passive transport (DIFFUSION) by which water diffuses across a membrane, in order to equalize the concentration of water inside and outside the cell.
For a cell in solution, a measure of the concentration of solutes outside the cell relative to that inside of the cell.
Of two solutions, that with a higher concentration of solutes.
Of two solutions, that with a lower concentration of solutes.
Refers to solutions with equal concentrations of solutes.
Active transport
A molecular movement that depends on the input of energy, which is necessary when the molecules to be moved are large or are being moved against their concentration gradient.
•Membrane pumps
Primary active transport
Active transport using energy released directly from ATP.
Secondary active transport
Active transport in which there is no direct involvement of ATP (adenosine triphosphate); the transport protein simultaneously moves one molecule against its concentrations gradient while letting another flow down its concentration gradient.
A cellular process in which large particles, solid of divided, outside the cell are surrounded by a fold of the plasma membrane, which pinches off, forming a vesicle and the enclosed particle now moves into the cell; the three types of Endocytosis are Phagocytosis, Pinocytosis, and Receptor-mediated endocytosis.
A cellular in which particles within the cell, solid or dissolved, are enclosed in a vesicle and transported to the plasma membrane, where the membrane of the vesicle merges with the plasma membrane and the material in the vesicle is expelled to the extracellular fluid for use throughout the body.
A small, membrane -bound sac within a cell
One of the three types of endocytosis, in which relatively large solid particles are engulfed by the plasma membrane, a vesicle is formed, and the particle is moved into the cell.
One of the three types of endocytosis, in which dissolved particles and liquids are engulfed by the plasma membrane, a vesicle is formed and the material is moved into the cell; the vesicle formed in pinocytosis are generally much smaller than those formed in phagocytosis.
Receptor-mediated endocytosis
One of the three types of endocytosis, in which receptors on the surface of a cell bind to specific molecules; the plasma membrane then engulfs both molecule and receptor and draws them into the cell.
Tight junctions
A continuous, water-tight connection between adjacent animal cells; tight junctions are particularly important in the small intestine, where digestion occurs, to ensure that nutrients do not leak between cells into the body cavity and so be lost as a source of energy.
Irregularly spaced connections between adjacent animal cells that, in the manner of Velcro, hold cells together by attachments but are not water-tight; they provide mechanical strength and are found in muscle tissue and in much of the tissue that lines the cavities of animal bodies.
Gap junctions
A junctions between adjacent animal cells in the form of a pore in each of the plasma membranes surrounded by a protein that links the two cells and acts like a channel between them to allow materials to pass between the cells.
Plasmodesmata (plasmodesma)
In plants, microscopic tube-like channels connecting the cells and enabling communication and transport between them.
Nuclear membrane
A membrane that surrounds the nucleus of a cell, separating it from the cytoplasm, consisting of two bilayers and perforated by pores enclosed in embedded proteins that allows the passage of large molecules from nucleus to cytoplasm and from cytoplasm to nucleus; also called the nuclear envelope.
A mass of long, thin fibers consisting of DNA and proteins in the nucleus of the cell.
An area near the center of the nucleus where subunits of the ribosomes are assembled.
Gives animal cells shape and support; controls the intracellular traffic flow, serving as a series of tracks on which a variety of organelles and molecules are guided across and around the inside of the cell; it gives all cells some ability to control their movement.
Cilia (Cilium)
Short projections from the cell surface, often occurring in large numbers on a single cell that beat against the intercellular fluid to move the fluid past the cell.
Mitochondria (Mitochondrion)
"The powerhouse of the cell" because they generate most of the cell's supply of adenosine triphosphate (ATP), used as a source of chemical energy. In addition to supplying cellular energy, these organelles are involved in other tasks, such as signaling, cellular differentiation, and cell death, as well as maintaining control of the cell cycle and cell growth.
Intermembrane space
In mitochrondrion, the region between the inner and outer membranes.
In a mitochondrion, the space within the inner membrane, where the carriers NADH and FADH2 begin the electron transport chain by carrying high-energy electrons to molecules embedded in the inner membrane.
Round, membrane-enclosed, acid-filled vesicles that function as garbage disposals and are filled with about 50 different digestive enzymes and a super-acidic fluid, a corrosive broth so powerful that if the organelle were to burst, it would almost immediately kill the cell by rapidly digesting all of its component parts.
Endomembrane system
A system of organelles (the rough endoplasmic reticulum, the smooth endoplasmic reticulum, and the Golgi apparatus) that surrounds the nucleus; it produces and modifies necessary molecules, breaks down toxic chemicals and cellular by-products and is thus responsible for many of the fundamental functions of the cell.
Rough Endoplasmic Reticulum (rough ER)
A large series of interconnected, flattened sacs (they look like a stack of pancakes) that are connected directly to the nuclear envelope. It is called "rough" because its surface is studded with little bumps. These bumps are protein-making machines called ribosomes, and generally cells with high rates of protein production have large number of ribosomes.
Smooth Endoplasmic Reticulum
Synthesizes lipids such as fatty acids, phospholipids, and steroids and detoxifies molecules such as alcohol, drugs, and metabolic waste products.
Golgi apparatus
Processes and packages proteins, lipids, and other molecules for export to other location in or outside of the cell.
Central Vacuole
In plants, a large, fluid-filled organelle, surrounded by a membrane, important in nutrient storage, waste management, predator deterrence, sexual reproduction, and physical support.
Turgor pressure
In plants, the pressure of the contents of the cell against the cell wall, which is maintained by osmosis as water ruches into the cell when it contains high concentrations of dissolved substances; turgor pressure allows non-woody plants to stand upright, and its loss causes wilting.
In the leaf of a green plant, the fluid in the inner compartment of a chloroplast; which contains DNA and protein making machinery.
Interconnected membranous structures in stroma of a chloroplast, where light energy is collected and the conversion of light energy to chemical energy is photosynthesis takes place.
Passive transport
Molecular movement that occurs spontaneously, without the input of energy, the two types of passive transport are diffusion and osmosis.
Robert Hooke
The British scientist from the mid-1600s who was the first person to used the term "cell".
Functions to store nutrients, retain and degrade waste products, accumulate poisonous materials, provides physical support, and in plants, contains pigments that enable plants to attract birds that help the plant reproduce.
the jelly-like fluid, called the cytosol, and the cell's genome. JUST JELLY :)
the organelle in plant and animal cells that converts the energy stored in food into a form usable by the cell
Dehydration Synthesis
Dehydration synthesis is the process of joining two molecules, or compounds, together following the removal of water. When you see the word dehydration, the first thing that may come to mind is 'losing water' or 'lacking water.' This is a perfect way to remember what occurs during a dehydration reaction.
ydrolysis, the opposite of condensation, is a chemical reaction in which water breaks down another compound and changes its makeup. Most instances of organic hydrolysis combine water with neutral molecules, while inorganic hydrolysis pairs water with ionic molecules, such as acids, salts and bases.
Uses deoxyribose sugar
•Very stable mlcl.
•Genes made of DNA
Uses ribose sugar•Breaks down easily•Transfers information from DNA to protein
Nitrogen containing bases DNA
1.Adenine (A)
2.Guanine (G)
3.Cytosine (C)
4.Thymine (T)
Nitrogen containing bases RNA
1.Adenine (A)
2.Guanine (G)
3.Cytosine (C)
4.Uracil (U)
Chargaff's Rule
Nucleotide Chain
Nitrogenous Base
Sugar 5
Phosphate Group
Base Pair
where two bases meet
What is Life? 6 parts
1.Complex organization
2.Growth & Development
3 Major Types of Cells
Bacteria (4 facts)
-No organelles
-DNA a small circular piece with no proteins
-Cell walls
•Carbohydrates with short protein cross-links
Eukaryotes (4 facts)
-Lots of internal organelles
-DNA in many linear pieces bound with proteins
-Cell walls
•Cellulose (plants)
•Chitin (fungi)
•None (animals)
Archaea (4 facts)
-No organelles
-DNA a small circular piece, BUT
•DNA bound w/ protein like Eukaryotes
•Genes organized like Eukaryotes
-Cell wall
•Protein-Live in very harsh places
Bacteria & Archaea
Usually lumped together
Surface to Volume Ratio
Osmosis with an Artificial Membrane
Osmosis in Cells Red Blood Cell
---->Hypertonic Solution <----
H2O leaves the Cell shriveling in up
Osmosis in Cells Red Blood Cell
---->Isotonic Solution <----
Equal water coming in and out the cell
Osmosis in Cells Red Blood Cell
---->Hypotonic Solution <----
H2O rushes into Red blood cell and pops it !
Osmosis in Plant Cells
---->Hypotonic Solution <----
Expands the Cell wall the cell becomes turgid! versus wilted.
Osmosis in Plant Cells
---->Hypertonic Solution <----
We see the cell wall retains its shape but the cytoplasm begins to shrink up.
Osmosis in Plant Cells
---->Isotonic Solution <----
cell maintains its normal shape
Cell membranes are selectively_____________
Parts of Cell Membranes (3 Parts)
Phospholipid bilayer major part of cell membranes
•Polar heads & non polar tails
•Hydrophobic region stops large water soluble mlcls
Support fibers
rope-like proteins support cell proteins support cell shape
ID Tags
Different carbohydrate chains carbohydrate chains "label" different cell "label" different cell types
DNA Containing Organelles

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