Cellular and Organ-Level Processes in Biology, Exams of Nursing

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Ingestion - Acquisition of food Assimilation - Building of new tissues from digested food Monosaccharide - single sugar subunit

• carb Ex: glucose, fructose, galactose Disaccharide - 2 monosaccharides
• carb Ex: sucrose, lactose Polysaccharide - Polymer of sugar subunits -carb
• insoluble in water
• Ex: glycogen, cellulose, starch

Lipids - 3 fatty acids bonded to glycerol

• chief means of food storage -Major component of adipose tissue -Steroids, waxes, carotenoids, poryphyrins Proteins - Polymers of amino acids joined by peptide bonds -Hormones (ACTH & Insulin), enzymes, structure proteins (collagen), transport (hemoglobin), antibodies Enzymes - ↓ activation E and ↑ rate of rxn
• do NOT affect overall E -↑ temp : ↑ enzyme action/ optimal pH= 7.2 (except pepsin and pancreas) Competitive Inhibitors (enzymes) - Compete with substrate for binding at ACTIVE site
• can be overcome by adding more substrate -Vmax not affected

Noncompetitive Inhibitors (enzymes) - bind at allosteric site

• diminishes Vmax Prokaryotes - Bacteria -Contains ribosomes, nucleic acids, plasma membrane, nucleoid, cell wall -Lack nucleus, membrane-bound organelles, Eukaryotes - Cell wall in fungi and plants
• Nucleus, and membrane bound organelles Centrioles - microtubules involved in spindle organization during cell division -NO membrane -plants lack centrioles

Centromere - Near middle of eukaryotic chromosomes where spindle fibers attach Lysosome - Membrane bound -Involved in ingestion -Hydrolytic enzymes -has the ability to "commit suicide" Mitochondria - -generate energy (oxidative phosphorylation → ATP) -self-replicating organelles -contain DNA in circular plasmids Desmosomes - "Spot welds" -attach cells together and give cells mechanical strength -Ex: skin Tight junctions - seal the spaces between cells and prevent cell leakage Ex: intestinal cells

Nucleus - "information center" -Contains chromosomes, DNA and RNA -Separated by a double membrane nuclear envelope Nucleolus - Within the nucleus -Ribosome synthesis takes place Endoplasmic Reticulum (ER) - Transport network for molecules targeted for certain modifications and specific destinations Rough ER - Has ribosomes on its surface -secretes proteins into cytoplasm Smooth ER - Lacks ribosomes -plays a role in Calcium sequestration and release Ribosomes - -RNA and protein molecules

-Can be found floating freely or bound to a membrane Vacuoles - Store food and waste -Plant vacuoles usually bigger than animal vacuoles Gap Junction - Allows cells to exchange nutrients and for molecular communication Endosymbiotic Theory - Mitochondria and chloroplasts originated as independent unicellular organisms living in symbiosis with larger cells Fluid Mosaic Model - Lipids and proteins are free to move back and forth fluidly

• diffuse laterally -Integral proteins: embedded in membrane by hydrophobic interactions
• hard to remove -Peripheral proteins: stuck to integral membrane proteins by H-bonding or electrostatic interactions - easy to remove

Cell surface receptors - Type of integral membrane protein -3 types

1. Ligand-gated (open ion channel)
2. Catalytic
3. G-protein G-protein - Uses secondary messengers that amplify the signal Ex: cAMP S phase - replicate genome (create chromatids) G₁ and G₂ Phases - Gap phases Mitosis - 2N→2N Occurs in all dividing cells 10% of cell cycle

Phases of Mitosis - Interphase: replication of genetic material →sister chromatids Prophase:chromosomes condense; spindles form Metaphase: chromosomes align at M-plate Anaphase: sister chromatids separate (shortest phase) Telophase: new nuclear membranes form (cleavage furrow forms); spindles disappear Sequence of Mitosis - S phase →G₂→P→M→A→T→G₁ Meiosis - Occurs in sex cells -Homologous chromosomes pair at meta plate (tetrads) -Crossing over can occur

• 2N → N Phases of Meiosis 1 - Meiosis 1: produces 2 daughter cells with N chromosomes with sister chrom

-P1: crossing over occurs -M1: Tetrads align at M-plate (synapsis); each pair attaches to separate spindle -A1: homo. pairs pulled to opposite poles (disjunction) - distribution of 2 daughter cells is random with respect to parental origin -T1: nuclear membrane forms around each nucleus Phases of Meiosis 2 - Similar to mitosis -Only 1 daughter cell becomes a functional gamete in females (the rest are polar bodies) Chiasmata - X-shaped region with different chromatids of homo. chromosomes Kinetichore - Specialized group of proteins and DNA on a chromatid to which several spindle microtubules are attached

• found within the centromeres of each chromosome

Synapsis - Pairing of homo. chromosomes in Meiosis 1 Inversion - chromosomal segment turned 180⁰ Translocation - 2 non-homo. chromosomes interchange genes Nondisjunction - failure of homo. chromosomes to separate during Meiosis 1 or sister chromatids in Meiosis 2

• results in trisomy or monosomy Asexual Reproduction - -Binary fission -Budding -Regeneration -Parthogenesis Binary fission - Prokaryotes
• DNA replicates and cell wall grows inward along midwall -Ex: paramecia, amoebae, algae, bacteria

Budding - Develops an outgrowth - forms a smaller cell

• Ex: hydra and yeast Regeneration - Regrowth of lost body part Ex: hydra and starfish Parthogenesis - Unfertilized egg → adult Ex: bees and ants Gonads - Male: testes Female: ovaries Leydig cells - In the testes -Secrete testosterone Spermatogensis - Sperm production in seminiferous tubules

• head = nucleus -tail = flagellum Acrosome - membrane-bound structure at ant. end of sperm cells -contains hyaluronidase (breakdown of protective surfaces of egg) Prostatic Fluid - helps neutralize the acidic vaginal secretions to enhance sperms' ability to swim
• also neutralizes seminal fluid Oogenesis - oocytes produced in ovaries Capacitation - functional maturation of the spermatozoa while in the female -allows for egg penetration Male Reproductive - path of sperm: SEVEn UP

-seminiferous tubules → epididymis→ vas deferens→ ejaculatory duct→ nothing → urethra → penis Female Reproductive - Fallopian tube → Uterus → Cervix → Vaginal canal Menstrual Cycle - -Follicular: FSH promotes development of follicle which secretes E -Ovulation: peak in E → ↑ LH → ovulation → mature follicle bursts releasing ovum

• Luteal: LH induces follicle to develop into corpus luteum which secretes E and P (LH and FSH inhibited)
• Menstruation: if fertilized, placenta produces hCG (E and P levels remain high) If not fertilized, corpus luteum atrophies (drop in E and P) and menses occurs Estrogen - Hormone
• thicken endmetrium

-secreted by corpus luteum Progesterone - Hormone -Development and maintenance of endometrial wall -Secreted by corpus luteum Gametophyte generation - Haploid (N)

• produce haploid gametes (mitosis)
• sexually reproduce Ex: mosses Sporophyte generation - Diploid (2N)
• produces haploid spores by meiosis Ex: ferns and angiosperms Angiosperm - -Flowering plants

Parts of a flower - -Stamen: male organ; stalk-like filament and sac-like anther (pollen) -Pistil: female organ; composed of stigma (catches pollen), style and ovary -Sepals: green leaves that cover flower during early stages of development Flower fertilization - 1 sperm nucleus + 1 egg nucleus → zygote → embryo 1 sperm nucleus + 2 polar nuclei → 3n endosperm Seed formation - - Epicotyl: precursor of leaves

• Cotyledons: seed leaves
• Hypocotyl: lower stem and root -Endosperm: feeds embryo -Seed coat: outer covering of ovule Incomplete dominance - blends of parental phenotypes

ex: red and white snapdragons = pink snapdragons Codominance - multiple dominant alleles -ex: blood Sex-linked recessive - gene carried on X chromosome Ex: hemophilia and color blindness Epistasis - When 1 gene masks or modifies the expression of another gene Pleiotrophy - single gene effects several phenotypic characteristics Mutations - Somatic cells → tumors Gametes → transmitted to offspring Types of mutations:

• insertion, deletion, substitution

Pyrimidines - CUT the PY

• 1 ring
• ↑ G/C more stable because G is triple bonded to C Redundancy/degeneracy - genetic code synonyms
• multiple codons for the same aa Nucleoside - sugar + base Protein synthesis - Replication → transcription → translation Replication: DNA → DNA in 5'→3' Helicase: unwinds double helix Primase: begins replication Transcription: DNA → RNA m-RNA has inverted complementary code Translation: RNA → Protein m-RNA→ aa

Exons - nucleotide base sequences that are transcribed into mRNA→proteins Introns - Removed during transcription

• exons = don't exit mRNA - carries complement of DNA from nucleus to ribosomes
• least abundant RNA rRNA - ribosomal RNA
• most abundant form of RNA tRNA - brings aa to ribosomes during synthesis, recognizes aa and codons
• in cytoplasm -smallest form of RNA

Ribosomes - 2 subunits 3 binding sites: 1 for mRNA and 3 for tRNA PCR technique - makes multiple DNA copies in vitro X-ray diffraction - most accurate way to discover molecular structure Polypeptide sequence - initiation (AUG) → elongation → termination (UAG, UGA, UAA) Gene Regulation - Transcription enables prokaryotes to control metabolism Inducible system - require inducer for transcription

• RNA polymerase binds to promoter → structural genes transcribed
• Repressor binds to operator → structural genes NOT transcribed
• Inducer binds to repressor → no binding to operator → genes transcribed

Repressible system - Constant state of transcription unless co-repressor- repressor complex present to inhibit Bacteriophage - Virus that infects host bacterium; attachment/absorption → penetration/eclipse → lytic or lysogenic Lytic cycle - phage DNA takes control of bacterium.makes numerous progeny. -bacterial cell bursts (lyses) releasing virons -called virulent

• ALL HOST CELLS destroyed = evolutionary disadvantage Lysogenic Cycle - Becomes integrated into genome in harmless way (provirus/prophage)
• every time the host reproduces, the prophase is reproduced too
• a stimulus can cause the prophage to go into lytic cycle and lyses

Techoic acid - used for recognition and binding sites by bacterial viruses that cause infections Cleavage - -Results in progressively smaller cells (↑ ratio of nuclear-to- cytoplasm and surface-to-volume ratio of each cell which improves gas exchange)

• As cell division contiunes, morula (solid ball of cells) forms
• Blastulation occurs when morula develops a cavity called blastocoel -By 4th day, becomes hollow sphere of balls called blastula -By 6th day, blastula (blastocyst) begins implantation into uteral endometrium -Little increase in size occurs during gastrulation Gastrulation - Single cell layer of of blastula transforms into 3-layered gastrula

1. Ectoderm
2. Mesoderm
3. Endoderm

Ectoderm - Nervous system, integument (epidermis, hair, epi of nose, mouth and anal canal), lens of eye, retina, teeth, neural tube Mesoderm - * think systems musculoskeletal, circulatory system, excretory system, gonads, CT, portions of digestive and respiratory, notochord Endoderm - epithelial lining of GI tract and respiratory tract, parts of liver, pancreas, thyroid, and bladder lining Induction - process in an embryo in which 1 tissue causes another to differentiate Embryonic membrane (eggs) - Chorion (moist membrane → gas exchange) Allantois (sac-like involved in respiration and excretion/blood vessels for transport) Amnion (amniotic fluid)

Chroionic gonadotropin hormone - secreted by chorion and helps maintain the corpus luteum Placental internal development - growing fetus receives O₂ directly from mother through specialized circulatory systems (supplies O₂ and nutrients/ removes CO₂ and wastes)

• Placenta and umbilical cord are outgrowths of the 4 extra-embryonic membranes (amnion, chorion, allantois, yolk sac) Labor - -Cervix thins out and dilates -Amniotic sac ruptures -Rapid contractions -Birth of baby -Uterus expels umbilical cord and placenta Hemoglobin - - Allosteric - more than 1 binding site
• Tetramer

• Prosthetic group = heme
• binds to CO with a much greater affinity than myoglobin Myoglobin - -Single chain
• Stores O₂ in muscle Blood Flow - Aorta → Arteries → Arterioles → Capillaries → Venules → Veins Capillaries - - Single layer walls
• exchange of gases, nutrients and cellular wastes Atria - upper chambers of heart Ventricles - Lower chambers of heart
• R side: heart pumps deoxygenated blood into pulmonary circulation (lungs)
• L side: heart pumps oxygenated blood into systemic circulation (body)

Pulmonary vein and umbilical vein - carry oxygenated blood (unlike other veins) Veins - carry deoxygenated blood Ductus venosus - Allows blood to bypass the liver Foramen ovale - Allows blood to bypass pulmonary circulation by entering the left atria directly from the right atria

• in the heart Ductus arteriosus - conducts some blood from pulmonary artery to aorta (bypassing the lungs) Lymphatic system - -Collect ISF and return it to circulatory system maintaining a balance of body fluids
• Collect chylomicrons from SI