biology graduation test review. cells what is biology? the study of living things what is considered...
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BIOLOGY GRADUATION TEST REVIEW
Cells
What is biology?
• The study of living things• What is considered living?
–anything that has the ability to nourish, grow, and reproduce
–cells must be present
Cell Theory• The cell is considered the basic
unit of life.• All living things contain at least
one cell.• Cells come from pre-existing
cells.
Plant Cells versus Animal Cells ANIMAL CELL
PLANT CELL
Plant Cells versus Animal Cells
PLANT CELLS• cell wall (provides structure)• chloroplast (location of photosynthesis/
energy production)
ANIMAL CELLS• centrioles (responsible for cell reproduction)
Organelles Common to Both
STRUCTURE FUNCTION
nucleus control of all cell activities; location of DNA
mitochondria energy production
Golgi complex (apparatus)
assembles, sorts, and transports cell products
ribosome protein synthesis
chromosome composed of DNA containing genetic material
Cell Organelles, continued
STRUCTURE FUNCTION
cell membrane
phospholipid bilayer; maintains homeostasis; protects the cell
lysosome digests old cells and food (cleans up the cell)
endoplasmic reticulum
produces, stores, and transports protein (rough) and lipids (smooth)
flagella/cilia movement of materials
Prokaryotes“Pro-No”
• No true nucleus• No membrane-bound
organelles• No well-organized membrane
Prokaryotes“Pro-No”
• All prokaryotes are bacteria and all bacteria are prokaryotes
• Prokaryotes = bacteria (Monera)
Eukaryotes“Eu-True”
• True nucleus• Well organized membrane• Membrane – bound organelles
Eukaryotes“Eu-True”
• Most plants and animals and other specialized organisms
Active versus Passive Transport
ACTIVE TRANSPORT• requires energy (low concentration to high)• endocytosis and exocytosis• active transport (ATP is used)
PASSIVE TRANSPORT• diffusion (particles from high concentration to
low)• osmosis (water from high concentration to
low)• facilitated transport (diffusion using a
membrane protein)
Organic CompoundsORGANIC
COMPOUND DEFINITION FUNCTION
carbohydrates sugars and starches provide energy
lipids fats (insoluble in water) store energy
proteins amino acidsresponsible for
most cell functions
nucleic acids DNA and RNA store hereditary information
Homeostasis
• The maintenance of a constant, stable environment internally
•example: body temperature
Cell Membrane and Homeostasis
• utilizes active and passive transport
• diffusion and osmosis depends on environment (hydrophobic or hydrophilic)
Hydrophobic versus Hydrophilic
Hydrophobic• “water-fearing”• outside of cell
Hydrophilic• “water-loving”• inside of cell
GENETICS
Genetics
• The study of the inheritance of traits and how genes pass on these traits from parents to offspring
Important Genetic Vocabulary• trait: a characteristic of an organism
that is inherited (examples: eye color, hair type, etc.)
• gene: basic unit of heredity made of DNA that determines the characteristics of a trait
• allele: the two different versions of a gene for a particular trait (one received from each parent)
Genotype versus PhenotypeGENOTYPE
• an organism’s genetic makeup• includes the two alleles• represented with two letters (example: Bb)
PHENOTYPE• the physical appearance of a trait• expressed by the organisms genes• represented by description (example: brown
eyes)
Dominant versus RecessiveDOMINANT
• an allele that expresses itself while hiding the effects of another allele
• represented with a capital letter
• example: Bb (dominant brown eyes dominates over recessive blue)
RECESSIVE• An allele whose effects are hidden by a
dominant allele• Represented with a lower-case letter• example: Bb (dominant brown eyes dominates
over recessive blue)
Homozygous versus Heterozygous
HOMOZYGOUS• “homo-” means the
same• the pairing of alleles
that are the same• examples:
• BB is dominant homozygous brown
• bb is recessive homozygous blue
HETEROZYGOUS• “hetero-” means different• the pairing of unlike alleles• example:
• Bb is heterozygous brown
Gregor Mendel
• Father of Genetics• experimented with pea plants• established a method for
predicting how traits are inherited
Mendel’s Laws• The Law of Dominance: a recessive trait will
only be expressed when the organism’s genotype is recessive homozygous (bb)
• The Law of Segregation: during fertilization, new alleles are randomly formed; one can only predict offspring (using Punnett squares)
• The Law of Independent Assortment: each trait is inherited independently of other traits
Probability and Punnett Squares
• Probability is the likelihood an event will occur• Geneticists use Punnett squares to predict the
probability of genetic combinations• Example: When two heterozygous brown eyes
mate . . .
B b
B BB Bb
b Bb bb
Theory of Inheritance• Chromosomes are the physical basis of
inheritance (carry DNA).• Variability results from dominant and
recessive alleles.• The chromosomes in the male gamete and
female gamete join together during fertilization to form a zygote.
• gamete = sex cell• zygote = fertilized egg
DNA• deoxyribonucleic acid• found in chromosomes in the
nucleus• determines the hereditary traits of
an organism• contains all the information needed
for the production of proteins• protein sequences determine traits
RNA• ribose nucleic acid• aids in protein synthesis in the ribosome• 3 types:
• messenger RNA: mRNA carries the DNA nucleotide sequence for a protein from the nucleus to the ribosome
• transfer RNA: tRNA transports amino acids (building blocks of proteins) to the ribosome
• ribosomal RNA: rRNA makes up the structure of the ribosome
DNA replication• see figure 8-5 on p.149• self-duplication of the genetic material• results in two new DNA molecules• occurs during interphase (just before cell divides)• proteins unwind the DNA helix and each strand
acts as a template for a new strand• unbound nucleotides attach . . .
• A-T (adenine binds with thymine)• C-G (cytosine binds with guanine)
DNA transcription• to “transcribe” is to copy• mRNA is synthesized in the cell nucleus from
the DNA molecule• Just as in replication, the helix unwinds and
free nucleotides attach to make mRNA. . . • C-G (cytosine binds with guanine)• U-A (uracil binds with adenine)• Only DNA has thymine
• mRNA separates and moves out of the nucleus• DNA double helix reforms
DNA translation• process of translating the
genetic code to the amino acid sequence
• tRNA decodes the mRNA to read the DNA in order to make the correct protein
Mutations• A mutation is any change in the DNA
sequence.• A change in one nucleotide may
cause a change in the structure of the protein.
• During pregnancy, observing a karyotype (a chromosome picture) can detect chromosomal defects.
TAXONOMY
Taxonomy
• The study of the classification of organisms
Classification• Kingdom• Phylum• Class• Order• Family• Genus• Species
• King• Phillip• Cried • Out • For• Good• Soup
Binomial Nomenclature• Classification system used to give all organisms
a two-part name• First name = Genus name• Second name = Species name• Example:
– scientific name of a wolf is Canis lupus
KingdomsName
Pro- / Eu- karyote?
Uni- / Multi- cellular?
Examples
Monera prokaryote unicellular bacteria
Protista eukaryote unicellularalgae, seaweed,
protozoans, water molds
Fungi eukaryote multicellularyeasts, molds,
mildews, mushrooms, rust
Plantae eukaryote multicellular mosses, ferns, trees, shrubs, plants
Animalia eukaryote multicellularworms, insects, sponges, birds,
mammals
Kingdom Monera• bacteria• need water, nutrients, and a moderate
temperature to survive• autotrophs (make their own food) and
heterotrophs (obtain food from outside source)• decomposers (AKA saprophytes) = break down
dead organisms to release carbon and nitrogen• reproduce asexually (binary fission)• some possess flagella used for motion
Kingdom Protista• algae, seaweed, protozoans, water (slime)
molds• found in aquatic or damp environments• organisms that don’t fit in any other kingdom• autotrophs (algae) and heterotrophs
(protozoans)• reproduce either asexually or sexually• some have flagella or cilia for motion• gave rise to all other eukaryotic organisms
Kingdom Fungi• mushrooms, yeast, molds, mildews, rusts• all are heterotrophs (do not contain
chlorophyll)• absorb food from environment• many are saprophytes (decomposers) that
obtain nutrients from dead or decaying plants and animals
• reproduce either asexually or sexually
Kingdom Plantae• autotrophs (utilize photosynthesis)• Two groups:
– bryophytes (nonvascular) have no roots, stems, or leaves and transport nutrients using diffusion (examples: mosses, liverworts, hornworts)
– tracheophytes (vascular) have roots, stems, and leaves that transport water and nutrients throughout the plant (examples: ferns, gymnosperms, and angiosperms)
• all reproduce both sexually and asexually (alternation of generations)
Kingdom Animalia• worms, insects, sponges, birds, mammals• all are heterotrophs that have a digestive
cavity in which food is digested and absorbed• all reproduce sexually, but some (like jellyfish)
can also reproduce asexually
Unicellular versus Multicellular
UNICELLULAR• single-celled• composed of one cell• all bacteria and protists• non-specialized cells
MULTICELLULAR• multi-celled• composed of many cells• all other organisms (fungi, plants, & animals)• cells are specialized to perform different
functions
Asexual Reproduction• involves only one parent• no specialized sex cells are produced• does not undergo meiosis• chromosomes are duplicated in mitosis• Examples:
– binary fission = cell simply splits– budding = offspring grows out of the side of the
parent
Sexual Reproduction• involves two parents so genetic diversity is
increased• specialized male and female sex cells
(gametes) are produced • gametes fuse during fertilization to produce a
zygote (fertilized egg)• gametes are formed in meiosis• chromosomes are duplicated in mitosis
Haploid versus Diploid
HAPLOID• sex cells• contain one of each chromosome• human haploid cells have 23
chromosomes
DIPLOID• all non-sex cells• contain 2 copies of each chromosome• human diploid number is 46 (two sets of
23 – a set from each parent)
Mitosis• begins after interphase = cell growth,
chromosome (DNA)replication, and prep for division (most of a cell’s life cycle is spent in interphase)
• results in two identical daughter cells containing same number of chromosomes and genetic information as the parent cell
Phases of Mitosis1. Prophase = chromosomes become visible
(present), nucleus membrane disappears, and in animal cells, centrioles move to opposite sides of the cell
2. Metaphase = chromosomes line up in the middle of the cell
3. Anaphase = chromosomes move toward opposite poles of the cell (move away)
4. Telophase = chromosome become less distinct and nucleus membrane reappears; nucleus divides into two
Cytokinesis• occurs after telophase• cytoplasm divides forming two
separate cells
Meiosis• cell division that results in the formation
of haploid gamete cells (sex cells)• Meiosis I
– reduction division– diploid cell divides creating two haploid
cells• Meiosis II
– two haploid cells from meiosis I divide resulting in 4 haploid daughter cells
Mitosis versus Meiosis
MITOSIS• resulting cells have same number and kind of
chromosomes as parent cell• used for cell growth, tissue repair, and asexual
reproduction
MEIOSIS• resulting cells have half the number of
chromosomes as parent cell• used for gamete formation
ECOLOGY
Biomes
• Biome = a large area characterized by a certain climate and types of plants and animals
• 6 major biomes on Earth
Biome CharacteristicsName Characteristics
Tundra permanently frozen subsoil
Taigalong severe winters;
summers with thawing subsoil
Temperate Forest moderate precipitation; cold winters; warm summers
Tropical Forest heavy rainfall; constant warmth
Grassland variability in rainfall and temperature; strong winds
Desert sparse rainfall; extreme daily temperature fluctuations
Biomes of the Earth
Ecosystem Vocabulary
• Ecosystem = a part of the environment with its organisms, their interactions, and the physical and chemical factors that affect them
• Community = populations of different species that interact in an ecosystem
• Population = all the individuals of the same species living in a community
Members of an Ecosystem
• Producers = organisms that can make their own food; autotrophs; examples: bacteria, protists, plants
• Consumers = organisms that eat other organisms to get energy; heterotrophs; examples: fungi and animals
Consumer Classification• Herbivore = primary consumer who only eats plants;
example: cow• Carnivore = secondary consumer who only eats
other animals; examples: shark and tiger• Omnivore = consumer that eats both plants and
animals; example: most humans• Scavengers = animals that find dead plants or
animals and eat them; examples: flies, wasps, cockroaches, earthworms
• Decomposers = break down dead organisms to receive energy; examples: fungi and bacteria
Predator versus Prey• All animals must eat to survive. Animals can
be either predators or prey.• Predators hunt prey.• With predators always on the lookout for a
meal, prey must constantly avoid being eaten. • Any adaptation the prey uses adds to the
chances of survival for the species.• Some adaptations are defense mechanisms
which can give the prey an advantage against enemies.
Survival Defense Mechanisms• speed
– You can’t eat what you can’t catch!• physical or chemical features
– physical examples: quills on a porcupine or hard shell of a turtle
– chemical examples: stink of a skunk; poisons of a dart frog
• camouflage – allows the animal to blend in with its environment
to avoid being detected– used by both predators and prey
Parasite versus Host
• A parasite is an animal or plant that lives in or on a host (another animal or plant)
• Parasites obtain nourishment from the host without benefiting or killing the host
• Examples: canine heartworms, malaria, hookworms, pinworms, tapeworm
Food Chain• a diagram that shows
the way energy is transferred from one organism to another
• each step in a food chain is called a trophic level
• begins with producers and ends with decomposers
Food Web
• complex, interconnecting food chains in a community
• more accurate than food chain
Pyramids of Biomass/Energy