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Midterm

BGYB10&B11 Midterm 1 Study Guide


Department
Biological Sciences
Course Code
BIOB10H3
Professor
Mary Olaveson
Study Guide
Midterm

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BGY10 t Midterm 1
Lecture #1: Introduction t Chapter 1
- cells = unit of life
- about 10-100 million different kinds of organisms t each have many different types of cells
o adult human body has about 60 trillion cells and 200 different kinds of cells
- all cells are molecules that carry out chemical activity
- 1665: Z},}}l[(]À]Á}(ooÁ}(}-like compartments = cork cells from oak
bark
- 1665-íòóñWv}vÀv>µÁvZ}l(]À]Á]vPoooZanimalcules[]v}vÁ
- Cell Theory:
o all organisms composed of one or more cells
o cells = structural unit of life for all organisms
o cells come from pre-existing cells
- cells = structural compartments, separate external environment from internal, macromolecules
perform unique functions in cells
o cells are highly complex and organized
o cells possess genetic program and means to use it (e.g. transcription, translation
ZuZ]vÇ[t genes to proteins)
o cells are capable of reproducing more of themselves (e.g. mitosis, meiosis)
o cells acquire and utilize energy to develop/maintain complexity (e.g. photosynthesis,
cellular respiration t sun to carbs to ATP)
o cells carry out a variety of chemical rxns (e.g. enzymes t use/produce ATP)
o cells engage in many mechanical activities (e.g. intracellular transport,
assembly/dismantling cell components, cell movement)
o cells respond to stimuli (e.g. w/ surface receptions t proteins)
o cells can self-regulate (e.g. DNA repair, immune cells)
o cells evolve (beneficial genetic mutation, cell changes kept, retained in future)
** review cell structure t pictures in textbook
- prokaryotes lack membrane-enclosed organelles (DNA but no nucleus), over 3 billion years old,
genetic material loosely organized in nucleoid regions in cytoplasm, have plasma membrane and
ribosomes, cell wall gives support
o µµooÇZ]uo[Uu}o]ooÇ]Àt includes bacteria, cyanobacteria,
archaebacteria
o cyanobacteria = blue-green algae: aerobic photosynthetic prokaryotes, responsible for
oxygen-based life on earth, most morphologically diverse group of bacteria
- eukaryotes have membrane-enclosed organelles, over 1.5 billion years old (first were
unicellular), have internal cytoskeleton for support
o organelles: nucleus, ER, GA, chloroplasts, mitochondria, vacuoles, lysosomes)
o structurally diverse t metabolicaloÇZ]uo[
o oldest eukaryotes in Kingdom Protista, rest are in Plantae, Fungi, and Animalia
** review table 1.1 in textbook (1, 7, 8 = structural features; 4, 5, 6 = metabolic pathways) and table
1.1 part 2 in textbook
- rRNA tree indicates 3 major groups of organisms:
o 1 of eukaryotes t Eukarya
o 2 of prokaryotes t Bacteria and Archaea
- unicellular organisms must do everything needed to survive (e.g. most protists)
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- multicellular organisms = some protists, plants, fungi, animals
o ]À]voPZµ]li}[
o uvÇoolooÇ}Pv]u}v]}vZÁZ}o[}Pv]u
o believed to have descended from colonial eukaryotes (less that 1 billion years ago)
o ÆZ]]Zdifferentiation[
- differentiation = specialization t process where relatively unspecialized cell becomes high
]o]ÌvÆZoo](][Pv
o fertilized human egg differentiated into 100s of different cell types
Lecture #2: Chemistry for Cell Biology (pt. 1) t Chapter 2
- 6 elements compose 98% of all living organisms t H, C, S, N, P, O
o }µîìZouv[}u}u]v]vPî9}(}Pv]u
- covalent bonds = polar, non-polar
- non-}Àov}vA]}v]}vUZÇ}Pv}vUZÇ}Z}]]v]}vUÀvto[
forces
- for a neutral atom, the # p+ = # of e-
- chemical hierarchy of structure: sub-atomic particles t atoms t molecules
- molecules = 2+ atoms linked by chemical bonds resulting from chemical rxns
- atoms w/ incomplete valence shells interact w/ other atoms in order to complete shell
o can share valence e- = covalent bond
o can transfer valence e- = ionic bond
o can influence atoms/molecules by proximity (hydrogen bonds, hydrophobic interaction,
Àvto[(}
- type of bond distinguished by strength of bond t determined by amount of energy required to
break bond
- covalent bond = s}vP}vU]u}v]v(}u]vPu}oµoU(}uZÁ]Z]vu}oµo[
o when 2 atoms share 1+ e- to complete outer e- shell = stable
o involves full charges
o gives molecules 3-D structure
o types of covalent bonds based on: number and electronegativity = tendency of atom to
attract e- when it occurs as part of a molecule (EN increased up and right on periodic
table)
- non-polar covalent molecule = equal sharing of e-
o molecules w/out EN atoms and polar bonds
o molecules that have C and H are non-polar (e.g. hydrocarbons)
- polar covalent molecules = unequal sharing of e- t asymmetric distribution
o if nucleus more positively charged on one atoms, will attract e- more
o atoms with becomes relatively EN compared to other atom t presence of partial charges
o biologically important polar molecules have 1+ EN atoms (usually O, N, A, and/or P) t
e.g. water
- non-covalent bonds = weak bonds t when 2 atoms transfer 1+ e- to complete outer e- shell =
stable t or when atoms influence each other thru proximity w/out e- charge t hydrophobic
o may involve full/partial/no charges
o occurs between molecules
o govern interactions between molecules or different parts of large biological molecules t
weaker linkages
o ÇW]}v]}vUZÇ}Pv}vUZÇ}Z}]]v]}vUÀvto[(}
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- ionic bonds = strong in solids but weak in aqueous solutions
o ionization = involved atom that is so strongly EN that it captures e- from another atom t
atoms/molecules w/ opposite charges that attract each other
o atom gaining e- = anion
o atom losing e- = cation
- hydrogen bonds = partially positive H on one H2O molecules interacts w/ negatively charged O
on second H2O molecule, occurs between polar molecules (e.g. H2O) t hydrophilic
- oZ}vAZÇ}Z}]UÀvto[t weak bonds, join molecules together, form
ZÁvu}oµo[
- different types of bonds combine in forming biological molecules
- hydrophobic reaction = scared of water
o non-}ou}oµov}ZPvv[]vÁl,îK
o form aggregates to minimize exposure to polar surroundings
o }v[(}uµal connections/bonds
- Àvto[(} = as 2 atoms/molecules approach each other, experience weak attractive
forces
o if atoms too close (<4 A), repulsion occurs t e- clouds repel forcing atoms apart
o individual van der Waal forces are very weak but large numbers can be formed between
large macromolecules
o leads to force of attraction between biological molecules
- water = required by all living organisms
o accounts for 45-95% of weight for living organisms
o involved in many chemical rxns in organisms
o polar and capable for forming H bonds *
o unique properties: cohesion, adhesion, moderation of temp, insulation, excellent
solvent
o water dissociates in positive and negative ions
- pH scale used to distinguish acids and bases
o acids = substances that donate H+ ions
o bases = substances that accept H+ ions
- buffers = compounds that react w/ free H+ or OH-, resisting changes in pH
o uses weak acid w/ conjugate base (e.g. carbonic acid-bicarbonate in blood or phosphate
buffers in fluid cells)
- organic molecules = biochemicals
- chemistry of life on earth centers around carbon
o C binds up to 4 other atoms b/c only has 4 valence e-
o versatility makes it possible for diversity of organic molecules
o silicon has similar atomic structure but larger and less versatile
- hydrocarbons = contain only H and C atoms
o form C-containing backbones t linear, branched, or cyclic
o H often replace by function groups
- 7 functional groups involved in biological molecules t determine distinguishing characteristics of
biomolecules (large molecules)
o functional groups can show consistent chemical behavior = can predict molecule
behavior
** know functional groups: hydroxyl = makes alcohols, carboxyl = makes acids, amino, sulfhydryl,
phosphate
o have 1+ EN atoms (N, P, O, S)
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