what is biology?. what is biology, you ask? biology is the study of life. living things are called...
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What is What is Biology?Biology?What is What is Biology?Biology?
What is Biology, you ask?What is Biology, you ask?
Biology is the study of life.Living things are called organisms.
Organisms include bacteria, protists, fungi, plants, and animals.Viruses are not alive – they are not organisms.
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The seven characteristics The seven characteristics of lifeof life
All life is made of cells.All life must reproduce.All life has heredity based on one universal genetic code (DNA).All life has metabolism.All life must respond to environmental stimuli.All life has homeostasis; it must maintain
a stable internal environment . All life must evolve; that is, species must change over time.
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All organisms are made of All organisms are made of cellscells
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All organisms are made of All organisms are made of cellscellsCells are the building blocks of life.All cells come from pre-existing cells.
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Viruses (in red here) are not made of cells; they are not alive.Viruses (in red here) are not made of cells; they are not alive.
The cell theory states that
all living things are made up of cells; basic units of structure and function in living things are cells that new cells can only be produced from living, existing cells.
Biochemical Biochemical ReactionsReactionsBiochemical Biochemical ReactionsReactions
Cells can undergo chemical reactions that release energy from carbon-containing compounds (organic) as food.There are 3 major classes of organic molecules:
CarbohydratesProteinsLipids
CarbohydratesCarbohydratesInclude sugar – C6H12O6
Formed from photosynthesisBroken down in cellular respirationEquation: Photosynthesis6CO2 + 6H2O → C6H12O6 + 6O2
Equation: Cellular Respiration
P + ADP + C6H12O6 + 6O2 → 6CO2 + 6H2O + ATP
ProteinsProteinsNeeded:
to access energy stored in cellsto build cell structuresto regulate rate of chemical reactions
LipidsLipidsCommonly known as fats and oilsCreate membranes of cells that provide sites for essential energy conversions.Refer to figure 1 in the packet
Cell membraneCell membraneSeparates the living from non-living
environment.
Made of proteinand lipidMade of proteinand lipid
Cell membraneCell membraneA cell must be able to obtain food
and get rid of wastes through its cell membrane
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DiffusionDiffusionThe movement of particles from a region
of high concentration to a region of low concentration.
Examples: perfume in air, smoke in air, sugar in water,
oxygen through cell membranes
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OsmosisOsmosisDiffusion of water from an area of high
concentration of water molecules to one of low concentration across a partially permeable membrane.
Partially permeable means only some things can pass, not everything: usually small molecules with no charge, like H2O, CO2, & O2.
“High” water concentration means that there are a lot of water molecules per some unit of volume.“Low” water concentration means that
there is a lot of something dissolved in the water, so fewer molecules
of water.15
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Comparison ofComparison ofPhotosynthesis and Cellular Photosynthesis and Cellular
RespirationRespirationDiscuss Table 1Photosynthesis
6CO2 + 6H2O → C6H12O6 + 6O2
Cellular Respiration
P + ADP + C6H12O6 + 6O2 → 6CO2 + 6H2O + ATP
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All life has metabolismAll life has metabolismCellular Respiration (in Mitochondria)
Through respiration, cells release the chemical energy stored in foods created by photosynthesis.
6O2 + C6H12O6 6CO2 + 6H2O + 36 ATP
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All life has metabolismAll life has metabolismSunlight is the ultimate energy for life on
Earth. Photo-synthesis is carried
out in the chloro- plast
of producers such as algae, phy- toplankton, plants.
Asexual and Sexual Asexual and Sexual ReproductionReproductionAsexual and Sexual Asexual and Sexual ReproductionReproduction
Asexual ReproductionAsexual ReproductionOne parent passes copies of all its chromosomes to each of its offspring.Organisms produce new cells by mitosis.Mitosis is the process of nuclear division in which 2 new daughter cells each receive a complete set of chromosomes.Offspring are genetically identical to each other and the parent.Examples: Refer to table 1video
Sexual ReproductionSexual Reproduction
Involves two parentsThe offspring receives half of its chromosomes from the father and half from the mother.Gametes are sex cells (eggs – sperms)Meiosis produces gametes (1/2 # chromosomes)
Upon fertilization, full number of chromosomes is restored with the formation of a zygote.
A zygote contains all the information necessary for growth, development, and reproduction.The zygote will be similar but not identical to its parents.
All organisms must All organisms must reproducereproduce
For sexualFor sexualreproductionreproduction
For asexualFor asexualreproductionreproduction
Gametes
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Punnett SquaresPunnett SquaresGenotype – genetic characteristics carried by an organism.Phenotype – the way an organism looks and behaves.Alleles – genes that exists in alternative forms. The allele combination determines its genotype.
DominantRecessive
Punnet squares predict probabilities of outcomes.
Gametes produced by each parent pea plant
are shown along the top and left side.Remember: when the germ
cell that produces the sperm or egg divides, the
2n (diploid) number of chromosomes is split in
half: Tt becomes T and t.
T = dominantt = recessive
All life has heredity in All life has heredity in DNADNAPunnet squares predict
probabilities of outcomes.¼ of offspring are TT.½ of offspring are Tt.¼ of offspring are tt.
But ¾ of offspring are tall, and only ¼
are short (3:1 ratio).
T = dominantt = recessive
The dominant characteristic usuallyoverpowers the recessive one.The dominant characteristic usuallyoverpowers the recessive one.
Two pink-flowering plants are crossed. The offspring flower are as follows: 25% red, 25% white; 50% pink. What pattern of inheritance does flower color in these flowers follow?
A. dominanceB. multiple allelesC. incomplete dominanceD. recessivenessE. polygenic trait
All life has heredity in All life has heredity in DNADNAPedigree charts relate to
punnet squares
Square = manCircle = womanFilled = diseaseHalf filled = carrierOpen = healthy
DNA and ProteinsDNA and ProteinsDNA and ProteinsDNA and Proteins
All organisms contain DNA.DNA (deoxyribonucleic acid) carries the genetic code for all organisms.Four nucleotides: Nitrogenous bases
A - adenineT – thymineG – guanineC - cytosine
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All life has heredity in All life has heredity in DNADNA
DNAThe code of life