Semester Exam Study Guide

1. Chapters 1 – Scientific Method and Characteristics of Life 6 – Atomic Structure and Macromolecules 7 – Microscopes and Cell Parts 9 – Cell Cycle and Mitosis 10 – Meiosis and Genetics 14 – History of Life 15 – Theory of Evolution Semester Exam Study Guide

2. Scientific method • Objective, Hypothesis, Experiment, Data, Conclusion • Objective – question or puzzle brought on from observations • Hypothesis – testable explanation of a situation • Experiment – test hypothesis • Data – qualitative or quantitative data recorded in experiment • Conclusion – explanation of results that show either proof or dis-proof of hypothesis

3. Experiment • Independent variable – factor that is being manipulated and tested in an experiment • Dependent variable – factor that is being measured that depends on changes to the independent variable • Constant – remains fixed, does not change • Control – any variable that you control in experiment (you may control the constants) • Experimental group – group exposed to the factor being tested • Control group – group used for comparison

4. Science • Theory – explanation of a natural phenomenon supported by many observations and experiments • Law – describes relationships under certain conditions • Ethics – set of moral values or principles that guide decisions in society

5. Characteristics of life • Made of one or more cell – organism unicellular and multicellular • Grows and develops – caterpillar changes to butterfly • Adaptation – bird species develop different beaks over time • Reproduces – pass traits to next generation • Responds to stimuli – dog salivates to smell of food • Requires energy – eating or photosynthesis • Maintains homeostasis – internal stability, sweating or shivering • Displays organization – atoms, molecule, cells, organism

6. Atomic Structure • Atom – building blocks of matter • Protons – positive, inside nucleus, equal to electrons • Neutrons – neutral, inside nucleus • Electrons – negative, orbit outside nucleus, equal to protons, very small in mass

7. Atomic number – number of protons in an atom • Atomic mass – weight of protons and neutrons • Covalent bond – chemical bond formed when electrons are shared • Ionic bond – electrical attraction between two oppositely charged atoms (ions)

8. Macromolecule

9. Microscopes • Compound Microscope – uses series of lenses and light • Dissecting Microscope – low magnification observation • Scanning Electron Microscope – directs electrons over surface to produce 3D images • Transmission Electron Microscope – electrons passed through specimen to fluorescent screen

10. Cell Theory • All living organisms are composed of one or more cells • Cells are the basic unit of structure and organization of all organisms • All cells come from preexisting cells

12. Microscope parts A – Body Tube – holds ocular lens certain distance from objective lens B – Nosepiece – rotates objectives C – Objective lens – scanning, low, high powers, magnify image D – Stage Clips – holds the slide on the stage E – Diaphragm – controls amount of light that passes through the specimen F – Light source – provides light G – Ocular lens – eyepiece, magnifies light H – Arm – carry microscope by arm and base I – Stage – platform where the slide with specimen is placed J – Course knob – large adjustments K – Fine knob – small adjustments L – Base - support, carry by arm and base

13. Type of cells • Prokaryotic cell – do not have a nucleus or membrane bound organelles (bacteria) • Eukaryotic cell – contain a nucleus and membrane bound organelles (plant and animal)

14. Cell Parts • Nucleus – contains DNA, control center • Nuclear envelope – membrane surrounds nucleus, contains pores • Nucleolus – center of nucleus, site of ribosome production

15. Cell Parts • Plasma membrane – flexible phospholipidbilayer covers cell surface, selectively permeable (lets some molecules pass though while keeps others out) • Cell wall – rigid structure surrounds plant and bacteria cells, provides support

16. Cell Parts • Mitochondria – powerhouse, converts food into energy • Endoplasmic Reticulum (ER) – folded membrane, rough contains ribosomes • Central Vacuole – large in plant cell, stores water, food and waste

17. Cell parts • Vesicle – storage and transport food and waste • Lysosomes– type of vesicle that contains digestive enzymes to breakdown food • Chloroplasts – in plant cells, photosynthesis occurs • Golgi apparatus – fedex, package, ships and stores protein

18. Cell parts • Cytoskeleton – microtubules and microfilaments framework • Ribosomes – protein synthesis • Cytoplasm – semifluid material inside cell • Cilia / flagella – hair like and tail like structures for movement

19. Plant Cell vs animal cell Plant CellAnimal Cell • Cell Wall Centrioles • Chloroplast Cilia / flagella • Large Central Vacuole Lysosome

20. Cell Cycle – cells reproduce by a cycle of growing and dividing • Interphase – (G1, S, G2) cell spends most of its time • Mitosis – cell’s nucleus and nuclear material divides • Cytokinesis – cell’s cytoplasm divides and cell splits into two • Interphase • G1 - growing • S – DNA duplicates • G2 – prepare to divide

21. Meiosis – reduction of chromosome with two cell divisions, make gametes • Centriole – microtuble bundle • Centromere – center of chromosome where sister chromatids are attached • Chromosome – tightened and condensed form of DNA • Chromatin – relaxed state of DNA • Chromatid – (sister) identical sides of replicated chromosme

22. Cell plate – structure that forms in a plant cell during cytokinesis • Gene – segment of DNA that codes for proteins • Gamete – sex cells, have half the number of chromosomes, egg and sperm • Spindle apparatus – microtuble structure that moves chromosomes

23. Homologous chromosomes – same length, from different parents, same centromere position, carry genes that control same trait • Crossing over – during prophase 1 in meiosis, exchange genetic info on homologous chromosomes

24. Law of segregation – two alleles for each trait separate during meiosis then unite in fertilization • Law of independent assortment – random distribution of alleles occurs during gamete formation

25. Mitosis • Prophase – nuclear membrane and nucleolus disappear, spindles form, chromosomes condense • Metaphase – chromosomes line up in the middle • Anaphase – sister chromatids pull apart • Telophase – two nuclei, nuclear material reappears, spindles disappear

26. Meiosis • Prophase I – homologous chromosomes condense and pair up, crossover • Metaphase I – homologous chromosomes line up in middle • Anaphase I – homologous chromosomes pull apart • Telophase I – two nuclei (cytokinesis follows) – end with 2 cells haploid number of chromosomes • Prophase II – chromosomes condense • Metaphase II – chromosomes line up in middle • Anaphase II – sister chromatids pull apart • Telophase II – two nuclei in each cell, cytokinesis follows ending with 4 haploid cells

27. Mitosis vs meiosis • Mitosis • Asexual reproduction • Two identical daughter cells are created • Meiosis • Sexual reproduction • Results in genetic variation, 4 unique cells • Crossing over occurs

28. Haploid – n number of chromosomes, gametes • Diploid – 2n number of chromosomes, body cells • Alleles – alternative form of a single gene passed from generation to generation

29. Genetics • Heterozygous – two different alleles for a trait (Rr) • Homozygous – two same alleles for a trait (RR or rr) • Hybrid – heterozygous (different) • Purebred – homozygous (same)

30. genetics • Phenotype – physical appearance (yellow, round, straight) • Genotype – organisms allele pairs, represented by letters ( YY, Rr, cc, Tt) • Dominant – will mask recessive trait (genotype has capital letter RR or Rr) • Recessive – trait that is masked by dominant trait (genotype only lower case rr)

31. Tell genotype • Blue body yy • Stubby nose ll • Round eyes RR, Rr • Oval eyes rr • SquarepantsSS, Ss • Long nose LL, Ll • Hybrid yellow Yy • Heterozygous round eyes Rr • Purebred blue yy

32. Tell phenotype • LL long nose • Yyyellow body • Rrround eye • rroval eye • SS squarepants • Ss squarepants

33. Genetics problems • Wilma Rr Wilbur RR • Kids possible genotypes RR, Rr • Kids possible phenotypes round eyes • Round eyes 100% • Oval eyes 0% R R R r

34. Genetics problems • Susie - blue yy Bob - heterozygous yellow Yy • Kids possible genotypes Yy, yy • Kids possible phenotypes yellow, blue • Blue body 50% Y y y y

35. Events in proper Era • Precambrian – Autotropic prokaryotes enrich the atmosphere with oxygen • Paleozoic Era – Cambrian explosion • Mesozoic Era – first mammals appear, contains 3 periods – Triassic, jurassic, Cretacous • Cenozoic Era – primates evolve and diversify, time period you live in

36. History of earth • Plate tectonics – movement of several large plates on Earth’s surface • Paleontologist – scientist studies fossils • K-T Boundary – layer high levels iridium, evidence meteorite wipe out dinosaurs • Precambrian – autotrophic prokaryotes enrich atmosphere with oxygen

37. History of life • Radiometric dating – use decay of radioactive isotopes to measure age of rocks • Relative dating – method determine age of rocks by comparing with those in other layers • Half-life – half time for isotopes to decay • Fossil – preserved evidence of organisms, show species changed over time, formed in sedimentary rock

38. History of life • Spontaneous generation – old idea that life arises from nonlife • Theory of biogenesis – living organisms can produce other living organisms • Endosymbiont theory – prokaryotic cells were involved in formation of eukaryotic cells • Primordial soup hypothesis – energy from sunlight and lighting allow first organic molecules to form • Early atmosphere missing element of Oxygen

39. Evolution – cumulative changes in the groups of organisms through time • Natural selection – struggle to survive those better equipped will survive and reproduce • Adaptation – trait shaped over time by natural selection to increase survival or reproductive success • Artificial selection – human selective breeding desirable traits, domesticated animals, modern crops and dog breeds

40. Fitness – measure of number of viable offspring organism produces, increase # offspring increase fitness • Ancestral trait – more primitive traits shared by species with common ancestor (bird ancestor - teeth and tail) • Derived trait – newly evolved traits (feathers)

41. Structures • Homologous structure – anatomically similar structures inherited from common ancestor (forelimbs of vertebrates) • Vestigial structure – body structure no longer used for original function reduced in size (whale pelvic bone) • Analogous structure – same function but different structures (bird wings and butterfly wings)

42. Adaptations • Mimicry – one species evolves to resemble another species (king snake) • Camouflage – allows organisms to become almost invisible to predators (leaf bug) • Sexual dimorphism – different phenotypic appearance between males and females like coloration, size, ornamentation or behavior (peacocks)

43. Extra • Humans have NOT always been dominant species on earth • Biology – study of life • Bacteria – first living organism on Earth