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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,

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Presentation on theme: "BIOLOGY GRADUATION TEST REVIEW. Cells What is biology? The study of living things What is considered living? – anything that has the ability to nourish,"— Presentation transcript:


2 Cells

3 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

4 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.

5 Plant Cells versus Animal Cells ANIMAL CELL


7 Plant Cells versus Animal Cells PLANT CELLS cell wall (provides structure) chloroplast (location of photosynthesis/ energy production) ANIMAL CELLS centrioles (responsible for cell reproduction)

8 Organelles Common to Both STRUCTUREFUNCTION 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

9 Cell Organelles, continued STRUCTUREFUNCTION 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

10 Prokaryotes “Pro-No” No true nucleus No membrane-bound organelles No well-organized membrane

11 Prokaryotes “Pro-No” All prokaryotes are bacteria and all bacteria are prokaryotes Prokaryotes = bacteria (Monera)

12 Eukaryotes “Eu-True” True nucleus Well organized membrane Membrane – bound organelles

13 Eukaryotes “Eu-True” Most plants and animals and other specialized organisms

14 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)

15 Organic Compounds ORGANIC COMPOUND DEFINITIONFUNCTION carbohydrates sugars and starches provide energy lipids fats (insoluble in water) store energy proteins amino acids responsible for most cell functions nucleic acids DNA and RNA store hereditary information

16 Homeostasis The maintenance of a constant, stable environment internally example: body temperature

17 Cell Membrane and Homeostasis utilizes active and passive transport diffusion and osmosis depends on environment (hydrophobic or hydrophilic)

18 Hydrophobic versus Hydrophilic Hydrophobic “water-fearing” outside of cell Hydrophilic “water-loving” inside of cell


20 Genetics The study of the inheritance of traits and how genes pass on these traits from parents to offspring

21 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)

22 Genotype versus Phenotype GENOTYPE 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)

23 Dominant versus Recessive DOMINANT 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)

24 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

25 Gregor Mendel Father of Genetics experimented with pea plants established a method for predicting how traits are inherited

26 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

27 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... Bb BBBBb bBbbb

28 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

29 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

30 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

31 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)

32 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

33 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

34 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.


36 Taxonomy The study of the classification of organisms

37 Classification Kingdom Phylum Class Order Family Genus Species King Phillip Cried Out For Good Soup

38 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

39 Kingdoms Name Pro- / Eu- karyote? Uni- / Multi- cellular? Examples Moneraprokaryoteunicellularbacteria Protistaeukaryoteunicellular algae, seaweed, protozoans, water molds Fungieukaryotemulticellular yeasts, molds, mildews, mushrooms, rust Plantaeeukaryotemulticellular mosses, ferns, trees, shrubs, plants Animaliaeukaryotemulticellular worms, insects, sponges, birds, mammals

40 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

41 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

42 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

43 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)

44 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

45 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

46 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

47 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

48 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)

49 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

50 Phases of Mitosis 1.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

51 Cytokinesis occurs after telophase cytoplasm divides forming two separate cells

52 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

53 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


55 Biomes Biome = a large area characterized by a certain climate and types of plants and animals 6 major biomes on Earth

56 Biome Characteristics NameCharacteristics Tundra permanently frozen subsoil Taiga long 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

57 Biomes of the Earth

58 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

59 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

60 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

61 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.

62 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

63 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

64 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

65 Food Web complex, interconnecti ng food chains in a community more accurate than food chain

66 Pyramids of Biomass/Energy

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