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BIOLOGYYYYY 1.0. CET Reviewer. LEVELS OF ORGANIZATIONS. Unicellular organisms – perform all life functions by themselves ( Nutrition, respiration, movement, excretion, growth, sensitivity, reproduction). BIOSPHERE BIOME ECOSYSTEM COMMUNITY POPULATION
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BIOLOGYYYYY1.0 CET Reviewer
LEVELS OF ORGANIZATIONS • Unicellular organisms – perform all life functions by themselves • (Nutrition, respiration, movement, excretion, growth, sensitivity, reproduction) BIOSPHERE BIOME ECOSYSTEM COMMUNITY POPULATION ORGANISM SYSTEMS ORGANS TISSUES CELLS ORGANELLES ATOMS Multicellular organisms – has individual cells that perform specific functions
Specialized plant cells • Root hair cell: increases water and nutrient absorption • Palisade cell: has lots of chloroplast increases the absorption of light for photosynthesis • Epidermal: tightly packed, secretes a waxy cuticle protects from excessive water loss Specialized animal cells • Red blood cell: no nucleus = bi-concave shape increases surface area: better oxygen absorption and transport • Sperm cell: with a movable tail; has lots of mitochondria greater energy • Neuron: for interconnectivity/information transfer through impulses sent throughout the body; has a myelin sheath that insulates the nerve fiber.
ENZYMES too! • “biological catalysts” = changes the rate of a reactionwithout the enzyme being changed itself • Combine with molecules (substrates) enzyme-substrate complex • Enzyme reactions: • Anabolic: building up larger molecules (synthetic reaction) • Catabolic: breaking down smaller molecules (degradative reaction)
PHOTOSYNTHESIS • For autotrophs/producers: Light energy from the sun chemical energy (glucose) 6CO2 + 6H2O C6H12O6 + O2 (Carbon dioxide + water Glucose + Oxygen) • Parts: • Light reaction: dependent on light; in the photosystems of the thylakoid • Light energy Water oxidized to oxygen Energy: ATP and NADPH2 • Dark reaction (Calvin Cycle): dependent on temperature; in the stroma • ATP and NADPH2 reduce CO2 reduced carbon = organic carbon (Glucose) Light energy Chlorphyll
Quick terms! ATP = Adenosinetriphosphate NADPH2 = Nicotinamideadeninedinucleotide phosphate
The Chloroplast Chlorophyll: • Absorbs red, violet and blue; reflects green • Most abundant forms: chlorophyll a and b • Embedded in the thylakoid
CELLULAR RESPIRATION • Sugars/carbohydrates + Oxygen ENERGY, water and carbon dioxide C6H12O6 + O2 6CO2 + 6H2O + Energy • Parts: • Glycolosis: cytoplasm, no oxygen; glucose pyruvate • Kreb’s Cycle/Citric Acid Cycle: inside the mitochondria; needs oxygen
HOMEOSTASIS • Organism maintaining constant internal conditions necessary for life • Cell and molecular physiology: • diffusion,osmosis, passive transport, active transport • System/organ physiology: (body temp = 37/98.6 F; hypothalamus = thermostat) • Endocrine system • Thermoregulation • skeletal muscles = shivering, • non-shivering thermogenesis: decomposing of fat heat; sweating
Chemical regulation • Pancreas: insulin and glucagon for lower blood-sugar concentration • Lungs: CO2 O2; • kidneys: remove urea, adjusts the concentration of water and ions) • Organism/ecological physiology: Adaptation • genes change phenotypes change • extended phenotypes • reverse engineering
CELLULAR BIOLOGY • CELL THEORY: proposed by Matthias JakobSchleidenand Theodor Schwann • All organisms are composed of one or more cells. • A cell is the organism’s basic unit of structure and function. • All cells come from previously existing cells. • The continuity of life is based on inheritable information in the form of DNA.
TYPES OF CELLS PROKARYOTES EUKARYOTES With distinct nucleus With organelles Only some have locomotion parts Protoctista (Protists), Fungi, Plantae, Animalia • DNA region: nucleoid • No organelles, except ribosomes • Locomotion (common) • Eubacteria, Archaebacteria, Halophiles, Methanogens, Thermophiles
MAIN REGION: Nucleus • control center of the cell • contains DNA
MAIN REGION: Plasma Membrane • contains the cell contents and separates them
MAIN REGION: Cytoplasm • cellular material outside the nucleus and inside the plasma • site of most cellular activities
MAJOR ORGANELLES WITHIN THE CYTOPLASM • Golgi Apparatus • “traffic conductor” for cellular proteins • functions in modifying and packaging of proteins • sends out proteins for export via secretory vesicles • Lysosome • “breakdown bodies” • contains hydrolytic enzymes that break down proteins, carbohydrates, and lipids • also digests disease-causing bacteria
MAJOR ORGANELLES WITHIN THE CYTOPLASM • Peroxisome • membrane sacs containing powerful oxidase enzymes • disarms dangerous free radicalsby converting them to hyrdogen peroxide • Centrioles • rod-shaped bodies • direct the formation of mitotic spindle • Cytoskeleton • cell‘s “bones and muscles • provides an internal framework
MAJOR ORGANELLES WITHIN THE CYTOPLASM • Smooth Endoplasmic Reticulum • continuation of the rough ER • functions in cholesterol synthesis and fat metabolism • detoxification of drugs • Rough Endoplasmic Reticulum • studded with ribosomes • where proteins from ribosomes assume their functional shapes • sends proteins to the GA via transport vesicles
CELLULAR DIVISION: Mitosis • occurs in animals and plants for growth and repair • results in 2 identical, diploid, daughter cells • basis for asexual reproductionin unicellular organisms, allowing rapid population growth
MITOSIS: Interphase • period between mitosis and meiosis • divided into 3 sub phases: • G1 • preparation for chromosome or DNA replication • S • DNA replication • G2 • preparation for mitosis or meiosis
MITOSIS: Prophase • centrosomes form spindle poles • spindle fibers begin to form and are organized • nuclear envelope disintegrates • nucleolus disappears
MITOSIS: Metaphase • chromosomes move to equator or metaphase plate • sister centromeres become attached to spindle fibers from opposite poles
MITOSIS: Anaphase • starts when kinetochores separate and chromatids move to opposite poles of the cell
MITOSIS: Telophase • chromatids reach the poles of the cell • nuclear envelope forms • nucleolus reappears
CELLULAR DIVISION: Meiosis • results in four haploid, daughter cells • basis for gamete production in sexual reproduction • as it results in halving of the chromosome number, meiosis is also called reduction division
MEIOSIS: Interphase • “resting stage” • chromosomes are very long and thin • towards the end, chromosomes have already made replica chromatids joined by centromeres
MEIOSIS: Prophase I • nuclear envelope disintegrates • nucleolus disappears • tetrads form • crossing-over occurs
MEIOSIS: Metaphase I • after crossing-over, homologous chromosomes move to the equator of the cell
MEIOSIS: Anaphase I • homologous chromosomes start to separate and move to opposite poles
MEIOSIS: Telophase I • cell divides into two daughter cells • nuclear envelope develops • marks the end of the first phase of meiotic division
MEIOSIS II • division of two daughter cells from meiosis I • similar to mitosis but there is no replication of chromosomes • results in 4 cells which are haploid
MOLECULAR BIOLOGY • seeks to understand the molecular basis of life – particular it relates the structure of specific molecules of biological importance to their functional role in the intact cell and organism • Genetic Code • Degenerate– many combinations correspond to a single amino acid • Wobbleposition– position in the code that varies • BASE PAIRING (DNA) • Adenine – Thymine • Guanine – Cytosine • BASE PAIRING (RNA) • Adenine – Uracil • Guanine – Cytosine
THE CENTRAL DOGMA • REPLICATION • semi-conservative process – daughter cells would contain one strand of the parent DNA and one strand of the new DNA • occurs in the nucleus • TRANSLATION • process where DNA is copied into a single stranded RNA • occurs in the nucleus • productmRNA moves to cytoplasm
THE CENTRAL DOGMA • TRANSLATION • occurs in ribosomeswhere mRNA is translated into proteins • governed by the genetic code which combination of three bases or triplet directs the addition of a particular amino acid to the growing protein chain • Start and Stop Codons signals start and end of translation ** Start codons: AUG (methionine) Stop codons: UAG, UGA, UAA