Biology EOCT Review

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Biology EOCT Review

• All wish to possess knowledge, but few,
  comparatively speaking, are willing to pay the
  price.

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Ecology

• The study of interactions between organisms and
  their physical environment
• Ecosystem natural unit that includes all living
  things within an area, their interactions with
  each other and all of the non-living features in
  the area
• Biotic factors all living things
• Abiotic factors non-living, water, air,
  temperature, soil, rainfall, sunlight, etc

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Ecology cont.

• Levels of organization within ecosystems
• From smallest to largest
• Organism gt Population (1 species) -gt Community
  (different species) -gtHabitat -gt Ecosystem -gt
  Biome -gt Biosphere

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Ecology cont.

• Major Land Biomes
• Tundra
• Permafrost, cold, lichens, mosses, grasses
• Taiga
• Coniferous forest (pines, spruce), long cold
  winters, soil thaws in spring and summer
• Temperate Deciduous Forest
• We live here, moderate rain, cold winters, warm
  summers, deciduous trees (drop leaves)
• Tropical Rainforest
• Great biodiversity of species, heavy rain, always
  warm, infertile soil
• Grasslands
• Prairies, windy, rainfall and temperature vary
  throughout year
• Desert
• Little rain, hot temps in the day, cold temps at
  night, drought resistant plants

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Biology cont.

• Populations
• Population density - of individuals living in a
  given area
• Exponential growth J-shaped curve, rapid growth
  rate
• Logistical growth S-shaped curve usually
  present in natural populations top of S
  represents the population reaching its carrying
  capacity
• Carrying capacity maximum of individuals a
  specific environment can support

Exponential
Logistical
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Ecology cont.

• Energy Flow Through an Ecosystem
• Ultimate source of energy is the SUN
• Producers make their own food (autotrophs) then
  transfer the energy to consumers
• Consumers heterotrophs, eat producers
• Primary herbivores
• Secondary carnivores
• Omnivores eat plants and animals
• Decomposers / Saprophytes break down dead
  organic matter

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Ecology cont.

• Energy Flow through Ecosystem
• Food chain shows transfer of energy from one
  organism to another
• Each step is a trophic level
• Always starts with a producer (plant) and ends
  with a decomposer
• Food web all the food chains in a community
  connected together
• A food chain is one part of a food web

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Ecology cont

• Cycles
• Energy flows through a community in 1 way, from
  the sun to the top of the food chain. Only 10
  of energy is passed on to the next trophic level.
• Matter is recycled in an ecosystem. Decomposers
  convert matter back into a usable form for other
  living things.

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Ecology

• Carbon-Dioxide-Oxygen Cycle
• Plants take carbon dioxide out of atmosphere and
  put oxygen into atmosphere through photosynthesis
• Heterotrophs take oxygen out of atmosphere and
  put carbon dioxide into the atmosphere through
  respiration.
• Water cycle evaporation, condensation,
  precipitation, transpiration
• Nitrogen cycle nitrogen fixing bacteria convert
  nitrogen gas into nitrates to be used by plants

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Ecology

• Succession in an Ecosystem gradual steps taking
  place until an ecosystem reaches a mature and
  stable community
• Pioneer species first to inhabit an area
  makes soil for other vegetation to inhabit
• Climax community mature community
• Types
• Primary occurs in area that was previously
  unihabited (rock, lava flows)
• Secondary a disrupted area that still has some
  soil and vegetation

Primary
Secondary
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Ecology

• Humans and the Environment
• Non-renewable resources cannot be replaced in a
  short amount of time (oil, coal, natural gas,
  nuclear)
• Renewable resources can be replaced naturally
  in a relatively short amount of time
  (hydroelectric, solar, wind, wood)
• Greenhouse effect trapping of heat being
  released by the earth by the atmosphere (keeps us
  warm at night)
• Effect is increased by mans burning of fossil
  fuels puts more carbon dioxide in the air
  causes global warming

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DNA and Genetics

• Genetics study of heredity and variation of
  traits in organisms
• Trait specific characteristic of an organism
  that is inherited
• Gene segment of DNA on a chromosome that
  determines the characteristics of a particular
  trait

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DNA and Genetics

• DNA deoxyribonucleic acid
• Found in every cell of an organism
• Located with the chromosomes in the nucleus
• Double helix shape
• Nucleic acid made of long strands of nucleotides
• Nucleotides nitrogen base, sugar, and phosphate
  group
• Adenine pairs with thymine
• Guanine pairs with cytosine

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DNA and Genetics

• The genetic code (sequences of nucleotides)
  determines with amino acids are coded for and
  hence which proteins
• DNA replication self-duplicating process
• Double helix unwinds and unzips
• Each single strand serves as a template for a new
  complimentary strand
• Enzyme binds nucleotides to the template to form
  the new strand

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DNA and Genetics

• RNA - Ribonucleic Acid
• Nucleic acid
• 3 differences from DNA
• Sugar is ribose instead of deoxyribose
• Nitrogen bases adenine, uracil,
• guanine, and cytosine
• Single stranded
• 3 types of RNA
• Messenger RNA carries DNA nucleotide sequence
  out of the nucleus to the ribosomes
• Transfer RNA transports amino acids to the
  ribosomes for protein assembly
• Ribosomal RNA makes up the structure of the
  ribosome

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DNA and Genetics
POLYMERASE
DNA
mRNA

• DNA Transcription mRNA molecule is synthesized
  from the DNA molecule in the nucleus
• DNA unwinds and unzips
• Complementary RNA nucleotides pair with one of
  the DNA template strands
• mRNA strand detaches from the DNA and goes out to
  the ribosomes in the cytoplasm to carry out
  protein synthesis

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DNA and Genetics

• DNA Translation takes place in the ribosomes
• Translates the genetic code into a protein by
  assembling a chain of specific amino acid
  sequence
• 3 nitrogen bases a triplet codon a specific
  amino acid
• Order of codons determines order of amino acids
  which determine the protein that is synthesized
• tRNA brings in anti-codons to attach to the
  complementary codon
• When anti-codons pair with codons, amino acids
  are attached together in a chain
• Assembly ends when a stop codon is reached and
  the protein is released to the cell for use

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Genetics and Gregor Mendel

• Mendel studied inheritance in pea plants
• Mendel father of genetics
• Hybrid offspring of cross between a homozygous
  dominant parent and a homozygous recessive parent
• Concluded that offspring have two genes form each
  trait, one from each parent
• Alleles different forms of the same gene

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Mendelian Genetics
segregation

• Law of Dominance- when 2 different alleles are
  inherited, one is expressed (dominant) and one is
  hidden (recessive)
• Law of Segregation the two different forms of
  an allele randomly separate during meiosis
  during fertilization new combos of the alleles
  come together
• Laws of Independent Assortment genes for
  different traits sort out separately from one
  another during meiosis

Incomplete Dominance
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Mendelian Genetics

• Genome genes present in an organism
• Human genome project mapping out locations of
  genes (and the traits they code for) in the 23
  pairs of chromosomes
• Phenotype physical appearance of a trait (tall
  plant)
• Genotype allele combonation in an organism (TT,
  Tt)
• Homozygous alleles are the same
• Heterozygous alleles are different (hybrid)

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Mendelian Genetics

• Probability likelihood that an event will occur
• Punnet Square chart that shows all the possible
  combinations of gametes and their probabilities
  when two organisms are crossed
• Monohybid cross two alleles for one trait
  crossed
• Dihybrid cross two pairs of different traits at
  one time

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Genetics

• Sexual reproduction male and female sex cells
  (gametes) fuse during fertilization
• Gametes are haploid (1 set of chromosomes) n
• Zygotes are diploid (2 sets) 2n

Mitosis
Meiosis And fertilization