Elements, Water, Cells, Membrane Transport, and Cell Division (Review #1) Flashcards
SPONCHNa CaFe
Sulfur
Phosphorus
Oxygen
Nitrogen
Carbon
Hydrogen
Sodium
Calcium
Iron
Sulfur
Amino acids (proteins – disulfide bridges)
Phosphorus
Phospholipids, Nucleic acids (DNA and RNA – phosphate in the backbone), ATP
Oxygen
Amino acids (proteins), Carbohydrates, Lipids, Nucleic acids (DNA and RNA), aerobic respiration (final electron acceptor at end of ETC)
Nitrogen
Amino acids (proteins – amine groups), Nucleic acids (DNA and RNA – nitrogenous bases), ATP
Carbon
forms foundation for all organic molecules/ compounds – can form up to 4 covalent bonds (compounds containing carbon and found in living organisms)
CHON
found in decreasing abundance from C to N in living organisms in this order)
Hydrogen
Amino acids (proteins), Carbohydrates, Lipids, Nucleic Acids, respiration (reducing agent – shuttles electrons), photosynthesis (reducing agent – shuttles electrons)
Sodium
Osmoregulation (nephron in kidney), action potentials (nerve signals – sodium channels open, sodium ions rush INTO nerve cell causing depolarization)
Calcium
Muscle contraction (released from sarcoplasmic reticulum to bind to troponin to expose myosin binding sites), Nerve cell transmission (calcium channels open at axon terminal, calcium ions rush INTO nerve cell causing vesicles with neurotransmitter to bind with pre-synaptic membrane and “dump” neurotransmitter into synaptic cleft)
Iron
Muscle contraction (released from sarcoplasmic reticulum to bind to troponin to expose myosin binding sites), Nerve cell transmission (calcium channels open at axon terminal, calcium ions rush INTO nerve cell causing vesicles with neurotransmitter to bind with pre-synaptic membrane and “dump” neurotransmitter into synaptic cleft)
Carbohydrates
(building blocks/ monomers are saccharides – sugars and starches)
Lipids
(building blocks are glycerol
and up to 3 fatty acids – fats/ oils)
Proteins
(building blocks are amino acids – enzymes, antibodies etc.)
Nucleic Acids
(building blocks are nucleotides – DNA, RNA, ATP)
Water is….
dipolar (has positive and negative charges, can form hydrogen bonds with other water molecules/ polar substances)
Thermal Properties of Water
-High specific heat : stabilizes environments for life (around them and within them) – a large amount of heat only raises water’s temp. a small amount – heat energy used to break hydrogen bonds BEFORE individual water molecules heat up
-High heat of vaporization: evaporative cooling for organisms (sweat, transpiration)
Cohesive and Adhesive Properties (due to hydrogen bonding)
-High surface tension: organisms live on surface/ maintains lung structure (pleural membranes)
-Transport in plants: Hydrogen bonds “stick” water molecules together (cohesion) and to other substances (adhesion - such as xylem walls) – allows movement (pull) of water through plants (transpiration)
Solvent Properties (due to polarity)
-Dissolves and transports polar/ hydrophilic substances - nutrients (organic compounds/ inorganic ions) etc. around/ through organisms
-Sap in plants (water up xylem and sugars down phloem)
Blood in animals (glucose, amino acids, fibrinogen, hydrogen carbonate ions etc.)
Note: hydrophobic substances (cholesterol, fats, oxygen) have special means of transport in living systems (lipoproteins in blood, haemoglobin etc.)
-Medium for metabolic reactions (Ex: glycolysis, DNA replication, transcription and translation, light-independent reactions, gas exchange/ clotting in blood plasma etc.)
Creation/ Breaking of Bonds: Water
-used in living systems to make and break chemical bonds
- water is removed from two subunits (H+ from one and OH- from another) of a macromolecule to create bonds, and water added to macromolecules (H+ and OH) to break bonds
Condensation
creating larger molecules by removing water (water is a product)
Hydrolysis
(hydro = water, lysis = “slice/ dice;” breaking): water is added to
break bonds/ break larger
molecules into smaller pieces
(ex: digestive processes)
Cell Theory Overview
-All living things made of cells
-Cells = smallest fundamental unit of life
-All cells arise from pre-existing cells
Evidence for Cell Theory
-Microscopes allow visualization of cells
-NOTHING smaller than a cell found to survive (on OWN) – if not made of cells
-Sterilization prevents cell growth (cells can only come from other cells) – Louis Pasteur
Exceptions to Cell Theory
Multinucleate muscle cells and fungal hyphae, giant algae, viruses, first cell origins (spontaneous)
Basic Functions of Life Carried Out by ALL cells
eproduction, growth, respiration (energy/ nutrients), cells, homeostasis, excretion, response, metabolism
Order of Organelles/ Cells/ Molecules in terms of SIZE
Cell membranes (smallest)
Viruses
Bacteria
Organelles
Eukaryotic Cells (largest)
Magnification=
measured/ actual
Surface Area
determines rate of exchange of materials (nutrients/ wastes)
Volume
influences metabolic reaction rate/ determines need of nutrients and amount of waste
As cell size increases….
SA:V ratio decreases (cells divide when too large to maintain high SA:V ratio)
What is a stem cell?
undifferentiated (pluripotent/ totipotent – can continuously divide and become any cell)
Therapeutic Use of Stem Cells
-Stem cells harvested from embryos – destroys/ kills embryo! (OR placenta/ umbilical cord)
-Exposed to biochemicals in lab to cause differentiation into desired cell type
-Transferred to patients who need them (skin cells for burn patients) – requires immunosuppression of patient first so do not reject/ monitoring for cancer following transfer
Differentiation
cells are able to carry out specialized functions by expressing some genes and not others
Prokaryotic Cells Overview
-Divide by binary fission (asexual reproduction)
-Have organelles WITHOUT membranes around them
-Mitochondria and Chloroplasts (Eukaryotic cells) thought to have originated from primitive prokaryotic cell that was engulfed (endocytosis) by a primitive predatory/ heterotrophic cell – Endosymbiotic Theory (Lynn Margulis)
Structures in Prokaryotic Cells and their functions
-Cytoplasm: Fluid containing enzymes for metabolic reactions
-Flagellum: Motility
-Ribosomes (70S): Protein synthesis
-Nucleoid: Region where DNA located(cellular control/ reproduction)
-Plasma membrane: Entry/ exit of substances
-Cell wall: Shape/ protection/ water uptake
-Capsule: Protection (from dehydration)
-Plasmid: Additional DNA (can replicate independently/ be exchanged – adaptation)
-Pili: Attachment (in some aid in exchange of genetic material)
Eukaryotic Cells Overview
-Have MEMBRANE-BOUND organelles (discrete structures that carry out specialized functions = allow compartmentalization/ increased efficiency)
-Note: all cells have a cell/ plasma
membrane, ribosomes (no membrane), cytoplasm, chromosomes/ DNA
Structures in Eukaryotic Cells and Their Functions
-Ribosomes (80S):
Protein synthesis (bound to ER = make proteins for excretion, or free floating = make proteins that stay/ used in cell)
-Endoplasmic reticulum*: (lots in glandular cells)
—–Rough – protein synthesis (excretion)
——Smooth – hormone production, detoxification, lipid production, transports substances to golgi etc.
-Nucleus: Contains DNA (cell control/ reproduction)
-Nucleolus: Makes ribosomes
-Lysosome: (animal cells) - only one membrane
“Slice and dice” – hydrolytic enzymes for intracellular digestion (Note: plant cells have plastids for this function)
-Golgi Apparatus (lots in glandular cells): Collects, stores, modifies, and “ships”/ transports cellular materials (often from RER)
-Mitochondria: Aerobic respiration (ATP)
-Centrosome/ Centrioles: Organize/ assemble microtubules (cell division/ motility/ cytoskeleton)
-Chloroplasts: Photosynthesis (in plants/ algae)
-Vacuoles: Storage of nutrients (starch, water, glycogen etc) – VERY large in plants
Similarities Between Prokaryotic and Eukaryotic Cells
-Both have DNA
-Both have a cell
membrane
-Both have
cytoplasm/ carry out all functions of life
-Both contain ribosomes
Prokaryotes vs. Eukaryotes: DNA Association
DNA is naked (no proteins) vs.
DNA associated with proteins (histones)
Prokaryotes vs. Eukaryotes: DNA Shape
DNA is circular vs.
DNA is linear
Prokaryotes vs. Eukaryotes: DNA Enclosure
DNA in nucleoid vs.
DNA in nucleus
Prokaryotes vs. Eukaryotes: Organelles
No membrane-bound organelles/ no mitochondria vs.
Membrane-bound organelles/ mitochondria
Prokaryotes vs. Eukaryotes: Introns
DNA does NOT contain introns vs.
DNA contains many introns
Prokaryotes vs. Eukaryotes: Ribosomes
70S ribosomes vs.
80S ribosomes
Prokaryotes vs. Eukaryotes: Size
Smaller (size less than 10um) vs.
Larger (size more than 10um)
Animals vs. Plants Cells: Cell Walls
No cell walls (flexible/ rounded shape) vs.
Cell walls (fixed, angular shape)
Animals vs. Plants Cells: Centrioles
Centrioles vs.
No centrioles
Animals vs. Plants Cells: Chloroplasts
No chloroplasts vs.
Chloroplasts
Animal vs. Plant Cells: Vacuoles
Small (if any) vacuoles vs.
Large, central vacuoles
Animal vs. Plant Cells: Carbohydrate Storage
Carbohydrates stored as glycogen
vs.
Carbohydrates stored as starch
Animal vs. Plant Cells: Cholesterol
Cholesterol in cell membrane
vs.
No cholesterol in cell membrane
Cell Wall Function
maintain cell shape and regulate water uptake. In plants, water in cells presses out against cell wall, creates (turgor) pressure – vertical support
ECM ((extracellular matrix)
-anchored to cell membranes by collagen and glycoproteins.
-Allows attachment between cells, cell-to-cell interaction/ communication/ coordination (in tissues), movement/ migration, and MAY play a role in gene expression/ cell differentiation
Bacteria (Prokaryotic): Cell Wall and Material
Has a Cell Wall – peptidoglycan
Fungi (eukaryotic)
Has Cell Wall – chitin
Yeast (eukaryotic)
Has Cell Wall – glucan and mannan
Algae (eukaryotic)
Has Cell Wall – Cellulose
Plant (eukaryotic)
Has Cell Wall – Cellulose
Animal (eukaryotic)
No cell wall (only a plasma membrane) – surrounded by glycoproteins (mixture of sugars and proteins secreted by the cell) that form a structure called the ECM (extracellular matrix)
Explain how the hydrophobic and hydrophilic properties of phospholipids help to maintain the structure of cell membranes.
-Phospholipids have hydrophilic heads (polar) and hydrophobic (nonpolar) tails – amphipathic molecules
-Hydrophilic heads attracted to water and hydrophobic tails repelled by water
-Phospholipid bilayer (TWO layers) forms with polar heads toward/ in contact with water on both
sides of the membrane (cytoplasm and extracellular fluids) and tails away from water (in the center
of the bilayer)
-Hydrophobic interactions between tails and hydrophilic interactions between heads and water
stabilizes membrane structure
Interactions of phospholipids allow membrane fluidity (breaking/ remaking of membrane in endo-
and exocytosis
Functions of Membrane Proteins: TRACIE
Transport (active and facilitated)
Receptors (hormones – insulin etc.)
Anchorage (for cytoskeleton and to ECM)
Cell recognition/ identification (glycoproteins/ antigens)
Intercellular connections (plasmodesmata)
Enzymatic activity (metabolic reactions)
Passive Transport Definition
Movement of particles from high (HYPERTONIC) to low (HYPOTONIC) concentration (with/ down the concentration gradient – toward equilibrium – to create an isotonic solution)
Active Transport Definition
Movement of particles from low to high concentration (against a concentration gradient) – requires protein pumps and ATP!
Passive Transport Example: Diffusion
small/ nonpolar molecules move through membrane from higher (hypertonic) to lower (hypotonic) concentration (nonspecific protein channels allow small, polar ions to diffuse – example: gases in alveoli in lungs)
Passive Transport Example: Osmosis
diffusion of water molecules to balance solute concentrations (moves from low solute to high solute concentration)
Passive Transport Example: Facilitated Diffusion
diffusion of large molecules through SPECIFIC protein channels (pores) in the membrane (proteins change shape to “facilitate” this movement)
Active Transport Example: Sodium Potassium Pump
maintains resting potential in nerve cells (pumps 3 sodium OUT and 2 potassium IN – against their concentration gradients)
Endocytosis (ATP)
- Vesicles move large substances INTO cell (invagination of membrane; pinches off to form vesicle around large solid substances (phagocytosis) or large amounts of liquid (pinocytosis)
Exocytosis (ATP)
-SECRETION-
- Vesicles (from RER then to Golgi apparatus) move toward and fuse with cell membrane, dumping contents into extracellular space (secretion – molecules/ substances EXIT the cell)
Kidney Dialysis involves…..
passive transport because it involves concentration gradients
Tissues/organs for transplant are placed in….
isotonic solutions
Why to cells go through mitosis?
to produce 2, genetically identical daughter cells
Phases of Mitosis: SHIPMATE minus SHE
Interphase
Prophase
Metaphase
Anaphase
Telophase
Phases of Interphase
1.G1
2. S
3. G2
G1 (Phase 1 of Interphase)
growth, protein production, metabolic reactions etc.
S (Phase II of Interphase)
synthesis – DNA replication – copied chromosomes attached at centromere; copies called “sister chromatids”
G2 (Phase III of Interphase)
growth, protein production, duplicating organelles etc.
Prophase
nuclear membrane disappears, chromosomes condense and become visible, mitotic spindle forms
Metaphase
chromosomes , as sister chromatids, line up individually (NOT as homologous pairs) along MIDDLE of cell
Anaphase
centromeres split, sister chromatids separate; one copy of each chromosome pulled to opposite ends of cell by mitotic spindle fibers
Telophase
nuclear membranes begin to reform and cytoplasm divides – cytokinesis – forming two IDENTICAL, diploid (2n = 2 copies of each chromosome) daughter cells
——In animal cells, cytokinesis happens by means of a cleavage furrow, and in plants a cell plate (new cell wall, formed by
vesicles) causes cytokinesis
Cells spend most of their lives in…
interphase (“working” for the body)
Reasons why cells divide (TOAD +R)
*Tissue repair/ replacement
*Organism growth
*Asexual reproduction (binary fission – bacteria/ vegetative propagation or stem cuttings in plants)
*Development (from a fertilized egg – embryonic development)
*Ratio: cells divide when SA/ V ratio is too small
Cyclins
The cell cycle has “checkpoints” (where process stops and cell viability/ health is “checked” before being allowed to continue dividing)
• Controlled by proteins called cyclins
• FOUR different cyclins
• Cyclins activate cyclin-dependent kinases
• Different cyclins and CDK’s at different times for different reactions so process happens in
correct order
Tumor suppressor genes
protein products inhibit cell growth/ division
Oncogenes
protein products promote growth/ division
Mutations to what genes can cause cancer?
Oncogenes and tumor suppressor genes
_________ cause mutations
Mutagens
*Radiation (UV/ Xrays etc.)
*Chemicals (cigarette smoke etc.)
Cancerous Cells…
-do NOT respond to cell cycle controls – divide uncontrollably and produce masses of cells (tumors)
– can happen in ANY part of the body
Benign tumors
remain at original site or contained in membrane
Malignant Tumors
invading surrounding tissue
Metastatic Tumors
in blood; travel to other parts of body and form secondary tumors
Mitotic Index=
of cells in any stage of mitosis ( can see chromosomes in these cells)/ total # of all cells (includes interphase)
Cancer cells have _______ mitotic indexes because….
Higher, as cells divide faster/ out of control
For what thermal properties is water higher than methane and why?
-Freezing Point
-Boiling Point
-Heat Capacity
They have similar mass and size but water is polar and can form hydrogen bonds
Davson-Danielli Model (Rejected) for Membrane Structure
a “lipo-protein sandwich” (a layer of lipids sandwiched between two protein layers). Based on an electron micrograph image.
Singer-Nicolson/ Fluid Mosaic Model (Accepted) for Membrane Structure
A. Membrane proteins found to contain hydrophobic portions/ non-polar amino acids (could not form a continuous layer in contact with water so must be embedded in membrane)
B. Membrane proteins found to be able
to move (fluid) within the membrane
(not in a fixed position)
C. Globular proteins found within/
passing through entire membrane
structure (so not just on outsides –
proteins are integral AND peripheral).
Discovery of Cyclins
-“serendipitous” (a happy accident)
-Two scientists studying gene expression in embryos accidentally discovered 3 proteins that varied in concentration at different times of cell cycle = cyclins discovered by chance!
First Cell Origins
-First cells must have arisen from non-living matter (abiogenesis).
-For this to occur, the following is theorized to have happened:
1. There was non-living synthesis of simple organic compounds
2. These simple organic compounds became more complex polymers
3. Some polymers became self-replicating (enabling inheritance)
4. These molecules became packaged in membranes (protobionts)
Miller-Urey Experiments:
Used system of closed flasks etc. to recreate
conditions of early earth and were able to generate simple organic compounds from non-living matter
Falsification of Theory of Vitalism
-Theory of vitalism states that organic compounds can ONLY be made by living systems, which possess a “vital force”
-In 1828, Frederick Woehler heated ammonium sulfate (inorganic salt) and created urea (an organic compound)
-Artificial synthesis of urea falsified theory of vitalism
