137 terms

Bio 1101: Molecules and Cells

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Water
most important substance for life; all living organisms are dependent on this; several unique properties
Cohesion
water molecules tend to stick together by hydrogen bonds -- this is how trees get water to their entirety from their roots
Surface tension
a measure of how difficult it is to break or stretch the surface layer of a liquid, it is also a result of covalent bonds; water's is high due to its cohesion
Water as a heat absorber
water has a high specific heat which is due to its many hydrogen bonds (which need to be broken for water to boil)
Water as a heat dissipater
evaporative cooling is an example of this
Evaporative cooling
molecules vaporize in layers (hottest molecules leave surface first taking heat with them leaving a cooler surface behind)
Carbon
most biologically important molecules are ___ based
Organic compounds
carbon compounds are these
Hydrocarbons
compounds containing ONLY C and H
Functional groups
many organic compounds have these; these are groups of atoms that participate in chemical reactions
Macromolecules
large biological molecules
Polymers
many macromolecules; these are chains of smaller subunits called monomers
Dehydration synthesis
process by which biological molecules are synthesized
Hydrolysis
process by which biological molecules are digested
Carbohydrates, proteins, nucleic acids
3/4 classes of life's organic molecules that are polymers
Carbohydrates, lipids, proteins, nucleic acids
4 types of biological molecules
Carbonyl group
defining feature of carbs
Glycosidic bonds
bonds formed by carbs
Energy storage and structural support
uses of carbs (2)
Monosaccharides
simple sugars (glucose, fructose) are monomers
Disaccharides
pairs (dimers) of monosaccharides (e.g. sucrose = glucose + fructose); formed by dehydration synthesis
Polysaccharides
"complex carbohydrates"; are polymers of monosaccharides; function in energy storage (starch, glycogen) or structural support (chitin, cellulose)
Alpha glycosidic bonds, beta glycosidic bonds
what causes differences between the different types of carbs
Lipids
don't have a specific structure, hydrophobic; fats, oils, waxes, steroids, fat molecules
Triglycerides
dietary fats; these come from meat, vegetable oils, etc.; these are formed from 3 fatty acids plus glycerol
Glycerol
3 carbon alcohol
Fatty acid
carbon chain with COOH group
Saturated fats
all carbon atoms are bonded to maximum number of hydrogen atoms; animal fats, tropical plant oils (cocoa, palm); linear shape with no double bonds; high melting point
Compact storage
the linear shape of saturated fats allows for this
Solid
saturated fats are typically ___ at room temperature
Unsaturated fats
have at least one C=C (carbon double bond); plant oils, fish fats (omega-3 fatty acids are beneficial); bent in shape; lower melting point; more easily digested; don't stick to arteries
Liquid
unsaturated fats are ___ at room temperature
Enzymes
these have easier access to unsaturated fat molecules because of the kinks in unsaturated fats
Supplied in the diet
certain unsaturated fatty acids are not synthesized in the body so they must be ___ ___ ___ ___ (e.g. omega-3 fatty acids)
Omega-3 fatty acids
required for normal growth, thought to provide protection against cardiovascular disease; include DHA and ALA; can help reduce risk of type 2 diabetes
Steroids
cholesterol is the "base" form; some are hormones (e.g. sex hormones)
Cholesterol
base steroid molecule/building block for complex steroids; diffuses through cell membranes; HDL vs. LDL
Cholesterol's importance for biological membranes
ampiphatic, helps add both rigidity and fluidity to cell membranes
Proteins
amino acid polymers; different sequences of amino acids result in different kinds of this
Function
shape important to ___ / shape determines ___
Functions of proteins
structural, storage, contractile, transport, defensive, signal
Amino acids
composed of central carbon flanked by a carboxyl group, an amino group, and a variable R group
Peptide
type of bond formed by only proteins; formed through dehydration synthesis
Polypeptides
chains of peptide bonds form this
Primary
level of protein structure; the amino acid sequence (what is the order of the amino acids?)
Secondary
level of protein structure; the coiling and/or folding of the amino acid chain
Tertiary
level of protein structure; coiling and folding of the coil which is determined by interactions of R groups (disulfide bridges, H-bonds); hydrophobic interactions
Quaternary
level of protein structure; two or more amino acid chains together (this level not always present)
Local environment
affects the shape of a protein; includes temperature, pH, tonicity
Denaturation
loss of normal shape of a protein; what happens when food is cooked
Sickle cell anemia
disorder in which improper folding of hemoglobin protein (rod instead of ball) causes misshapen RB which cannot bind O2; causes immunity to malaria
Nucleic acids
most are information storage molecules; function in genetics and cell control; determines which proteins are produced by cells
Types of nucleic acids
DNA, RNA, polymers of nucleotides
ATP
type of nucleic acid that is an energy carrier (along with NAD and FAD)
cAMP
type of nucleic acid that is a chemical messenger
Enzymatic properties
some nucleic acids are important for performing reactions in cells because they have these
DNA structure
long nucleotide strands, sugar-phosphate backbone, double-helix (A-T, G-C) with bases on opposite strands being complementary
RNA structure
similar to that of DNA, but single-stranded, T is replaced by U, and sugar is ribose; has both information storage and enzymatic properties
DNA RNA
___ is very stable, while ___ is much more reactive because it has an OH instead of just an H
Pancreas
insulin is made here
Glucose
presence of insulin causes muscle, liver, and fat cells to take up ___ from the blood system
High low
___ blood sugar levels cause the release of insulin, ___ blood sugar levels cause the release of glucagon
Type 1
diabetes where a person's pancreas cannot make insulin and is in need of exogenous insulin
Type 2
diabetes where a person becomes insulin resistant; accounts for 90-95% of all incidences; need increased amount of exogenous insulin to force the body to respond
Cell
the repeating unit of life; the basic unit from which life evolved that has been built upon/modified
Modern cell theory
all living organisms are made up of one or more cells; the smallest organisms are single cells, and cells are the smallest functional unit of multicellular organisms
Cell membrane, DNA, ribosomes, cytosol
what all cells have (4)
Prokaryotic
not a true evolutionary group; generally very small
Membrane-bound organelles
prokaryotic cells lack these
Archaea, bacteria
the 2 groups that prokaryotic cells are broken into
Eukaryotic
single group, plants and animals, have true nucleus and membrane-bound organelles
Monophyletic clade
true evolutionary lineage = this; all the descendants of an organism; prokaryotic cells are not this
Horizontally
DNA is transferred in this manner; organisms do not only obtain DNA from their parents, but from other organisms
Flagella, pili
surface features of prokaryotes (2)
Cell wall, slime layers, pili
means of adherence and protection for prokaryotes (3)
Nucleoid, plasmids, RNA, ribosomes, protein, food granules
specialized internal structures of prokaryotes located in cytoplasm (6)
Nucleoid
a single circular DNA strand
Plasmids
small, circular pieces of DNA
Linear
eukaryotic cells have this kind of DNA in their true, membrane-enclosed nuclei
Ribosomes
prokaryotes and eukaryotes have different types of these
Central vacuole, chloroplast, cell wall, plasmodesmata
features plant cells have that animal cells do not (4)
Flagellum, centrosome, lysosome
features animal cells have that plant cells do not (3)
Structure
___ related to function in the plasma membrane
Phospholipid bilayer
this completely surrounds each cell, isolates cell contents from its environment, regulates exchange, and communicates with other cells
Phospholipids
composes phospholipid bilayer
Head
hydrophilic and polar part of phospholipid
Tail
hydrophobic and non polar part of phospholipid
Semi-permeable
this type of membrane allows some substances to cross, but not others; the nuclear envelope is this
Polar
these kinds of substances will not readily diffuse through a semi-permeable membrane
Nonpolar, small
these kinds of substances will be able to pass right through a semi-permeable membrane
Fluid mosaic model
proteins are embedded within the bilayer and move freely or are anchored to filaments
Temperature, cholesterol, head groups, type of fatty acids
what affects permeability of the phospholipid bilayer (4)
Protein functional groups
structural proteins, cell signaling proteins, transport proteins, recognition proteins are types of these
Structural
type of protein that attaches to cytoskeleton to provide support, maintains cell shape, and anchors membrane proteins; also attaches to proteins of other cells (intercellular joining)
Cell signaling
type of protein where receptor proteins trigger cellular responses when molecules bind to them
Transport
type of protein that regulates movement of molecules through membrane, channels proteins or carrier proteins
Recognition
type of protein that serves as an "ID tag"; many are glycoproteins with carbohydrate groups attached
Nucleus
control center of the cell; DNA must be unwound for cell to have access to it; number of chromosomes depends on the species
Nuclear envelope, nucleolus, chromatin
components of the nucleus (3)
Chromatin
bound and coiled DNA with proteins
Nucleolus
site of ribosomal subunit production (DNA translators)
Fundamental rule of molecular biology
DNA --> RNA --> protein
Transcription translation
___ then ___ (part of the fundamental rule of molecular biology)
Retrovirus
kind of virus that violates the central dogma (go RNA --> DNA)
Genes
proteins alter the expression of ___
Endoplasmic reticulum
continuous with the nuclear envelope; source of some protein synthesis and phospholipids
Rough
type of ER studded with ribosomes; synthesizes primarily proteins
Smooth
type of ER that synthesizes primary lipids
Vesicles
these bud from each type of ER and travel to the Golgi
Golgi complex
sorts and separates proteins and lipids from the ER into functional groups; modifies some molecules; packages sorted/modified material for transport to other parts of the cell in vesicles
Glycoprotein
protein + sugar (example of a molecule that is modified in the Golgi)
Cnidarians
organisms that have extremely specialized Golgi complexes
Nucleus ER Golgi
order in which manufacture occurs in a cell
Lysosome
specialized vesicle from Golgi; contains digestive enzymes; fuses with food vacuoles or damaged organelles and digest contents
Contractile vacuole
water storage structure within a cell; important in water regulation and support; stores energy, waste, and special compounds (deterrent for predators)
Central vacuole
provides turgor pressure
Mitochondria, chloroplasts
energy organelles (2)
Very small, two membranes, own circular DNA
characteristics of energy mitochondria and chloroplasts
Mitochondria
both plant and animal cells have these which use energy stored in food molecules to create ATP
Photosynthesis
plant cells and some protists have chloroplasts where this occurs and light energy is converted into ATP
Endosymbiont theory
an early ancestor of eukarytoic cells engulfed a non-photosynthetic prokaryotic cell
Lynn Margulis
main proponent of endosymbiont theory
Cytoskeleton
network of protein fibers; primary structure of a cell; composed of microfilaments, intermediate filaments, and microtubules; dynamic
Microfilaments
protein fiber; important in cell movement; small, solid component of cytoskeleton
Intermediate filaments
protein fiber; small, solid component of cytoskeleton
Microtubules
protein fiber; large, hollow component of cytoskeleton; differ in size and shape
Organelles
these attach to and move along the protein fibers; the cytoskeleton is the cell's internal network/highway
Protein fibers
help a cell maintain shape
Cilia, flagella
motile appendages (aid in locomotion)
Structure of cilia and flagella
core of microtubules covered in cell membrane
Flagella
often single, propel cell by undulating whip-like motion
Cilia
generally numerous; short and produce movement by coordinated back-and-forth motion; can be used to move organism or substrate
Emphysema
damaged cilia lead to this
Anchoring junctions, tight junctions, communicating junctions
structures on cell surface (3 junctions)
Anchoring junction
attaches cells together
Tight junction
makes cell attachments leak-proof
Communicating junction
(aka gap) allows cells to exchange substances and chemical messages; called plasmodesmata in plant cells
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