Exam 2: Learning Objectives Flashcards
describe the flow of energy through living systems
- known as bioenergetics
- sun to plants to consumers to decomposers to heat
define metabolism
- all chemical reactions that take place in cells
- transforms matter and energy
explain metabolic pathways and the two major types
- metabolic pathways consist of many biochemical reactions
- anabolic: build bonds, requires energy, photosynthesis
- catabolic: breaks bonds, releases energy, glycolysis
compare and contrast the different forms of energy
- potential: stored energy, energy of matter due to structure, includes chemical energy
- kinetic: energy of objects in motion
- chemical: bonds holding atoms together have potential energy, chemical reactions break bonds and release energy
explain how energy is transformed in living systems
- potential energy in chemical bonds
- bonds broken and energy is released
- energy is required to build complex molecules
describe endergonic and exergonic reactions
- endergonic: non-spontaneous, require energy, anabolic, build bonds, products have more free energy
- exergonic: spontaneous, releases energy, catabolic, breaks bonds, reactants have more free energy
define the first two laws of thermodynamics in simple terms
- 1st: energy not created or destroyed only transformed
- 2nd: all energy transfers are never completely efficient; some energy is always lost (usually as heat) which increases entropy in the universe
describe activation energy
- initial energy required for reaction to start
- causes reactants to become more unstable and allows reaction to take place quickly
- usually sourced from heat surrounding the cell
explain how energetically unfavorable reactions can occur in a cell
- enzymes
- lower activation energy so reactions can occur easier
describe enzymes and their function (what do they do/not do)
- DO catalyze biochemical reactions
- DO lower activation energy
- DO bind to substrates
- DON’T change whether reaction is endergonic or exergonic
- DON’T change free energy of reactants or products
- DON’T get used up/changed from process
compare the different types of enzyme regulation
- competitive inhibition: molecule binds to active site, blocks substrate from binding
- allosteric (non-competitive) inhibition: molecule binds to allosteric site, changes enzyme active site so substrate cannot bind
- allosteric activation: molecule binds to allosteric site, changes enzyme active site so substrate can bind
- feedback inhibition: end product of enzyme reaction inhibits the continuation of reactions
summarize energy transformations in the biosphere
- light energy converted to usable energy through photosynthesis
- cellular respiration converts glucose into energy for cells
- energy leaves through heat
sketch the structure of ATP
- one adenine
- one ribose sugar
- 3 phosphate groups
describe the role of ATP in the cell
- energy supplying molecule of the cell
- powers work by coupling exergonic and endergonic reactions
- energy released from ATP when phosphate bonds are broken
understand the importance of cellular respiration
converts nutrients into ATP energy
write an equation summarizing cellular respiration
C6H12O6 + 6O2 –> 6CO2 + 6H2O + energy
explain why glycolysis is considered “universal”
- all cells undergo glycolysis
- aerobic respiration and anaerobic respiration
describe the location of glycolysis
cytosol
summarize the energy investment and output phases of glycolysis (including significant inputs and outputs)
- energy investment: glucose phosphorylated then converted to glyceraldehyde-3-P, requires 2 ATP
- energy payoff: glyceraldehyde-3-P becomes pyruvate, NAD+ picks up 2 electrons, 4 ATP produced
- yields 2 net ATP, 2 NADH, 2 pyruvate
explain the role of NAD+ in cellular respiration
- electron transport molecule
- NAD+ picks up electron and becomes NADH
- NADH goes to electron transport chain and gives electron to power ATP formation
understand the importance of glycolysis
- reduces glucose to pyruvate which goes in CAC
- produces NADH for ETC
describe the location of the citric acid cycle and oxidative phosphorylation
- CAC: mitochondrial matrix
- OP: mitochondrial inner membrane
describe how pyruvate is prepared for entry into the citric acid cycle
- oxidation of pyruvate
- converted to acetyl CoA: oxidized to acetate and attached to coenzyme A
- CO2 released
- electron passed to NAD+ producing NADH
describe the products of the citric acid cycle
- 4 CO2
- 6 NADH ***
- 2 FADH2 ***
- 2 ATP/GTP
- H2O
understand the purpose of the citric acid cycle
produces NADH and FADH2 for the ETC
describe the flow through the electron transport chain
- electrons from NADH go into C1 embedded protein
- move through C2, C3, and C4
- move back into mitochondrial matrix
- accepted by oxygen
- water created
explain the role of ATP synthase in the production of ATP
- where H+ flows down from the electrochemical gradient
- drives chemiosmosis
- where energy from H+ bind ADP and P to create ATP
understand the relationship between glycolysis, citric acid cycle, and oxidative phosphorylation
- 1st: glycolysis: glucose becomes pyruvate (becomes acetyl CoA in linker reaction)
- 2nd: citric acid cycle: uses acetyl CoA to generate NADH
- 3rd: oxidative phosphorylation: NADH gives electrons to electron transport chain which powers electrochemical gradient for ATP synthesis
know the net yield of ATP from each part of cellular respiration
- glycolysis: 2 ATP
- citric acid cycle: 2 ATP
- oxidative phosphorylation: 36-38 ATP
explain why oxygen is a beneficial electron acceptor
highly electronegative
explain how a circular pathway, like the citric acid cycle, fundamentally differs from a linear biochemical pathway, like glycolysis
- citric acid cycle continues in a cycle; creates oxaloacetate which is used to start reaction again
- glycolysis: starts with glucose and ends with pyruvate which isn’t used to start a cycle
compare/contrast the fates of pyruvate under aerobic and anaerobic conditions
- aerobic: becomes acetyl CoA
- anaerobic: becomes lactate or ethanol
describe the 2 major types of fermentation
- lactic acid: pyruvate converted to lactate, directly regenerates NAD+, pyruvate is final electron acceptor
- alcohol: pyruvate converted to acetaldehyde converted to ethanol, acetaldehyde is final electron acceptor
understand the relationship between glycolysis and fermentation
- glycolysis takes place in both aerobic and anaerobic respiration
- fermentation takes place in anaerobic respiration
- glycolysis provides pyruvate for fermentation
explain the purpose of cell division in unicellular vs multicellular organisms
- unicellular: reproduction
- multicellular: reproduction, growth and development, tissue repair, and tissue maintenance
compare the genomes of prokaryotic and eukaryotic cells
- both: double helix, same nucleotides, same genetic code
- prokaryotes: nucleoid region, 1 circular chromosome, have plasmids
- eukaryotes: nucleus, several linear chromosomes, have histones
understand the structure of a eukaryotic chromosome
- DNA and histone proteins make chromatin which condenses to form chromosomes
- number of chromosomes varies by species
know the purpose of DNA replication and recognize a duplicated vs unduplicated chromosome
- purpose: to ensure daughter cells are genetically identical to original
- duplicated: x-shape
- unduplicated: one linear shape
sketch, label, and describe the eukaryotic spindle apparatus
- astral microtubules: connect centrioles to cell membrane, keep centrosome in place
- polar microtubules: extend from centrioles to middle of cell, help the help move apart and elongate
- kinetochore microtubules: connect centrioles to kinetochores of sister chromatids, pull sister chromatids apart during anaphase
compare somatic cells and gametes
- somatic: body cells, diploid
- gametes: sex cells, haploid
interpret a simple karyotype
- homologous chromosomes: paired, carry same genes, one from each parent
- heterologous chromosomes: not matching, X and Y chromosomes
explain the 3 stages of interphase
- G1: cell growth, biochemically active
- S: DNA replication
- G2: energy replenished, organelles reproduce, cytoskeleton breaks down, visible growth
describe the different stages of the mitotic phase and discuss the behavior of chromosomes and cellular components during each phase
- prophase: chromosomes condense, spindle fibers emerge, nuclear envelope breaks
- prometaphase: kinetochores appear, spindles attach to kinetochores, centrosomes move to opposite poles
- metaphase: chromosomes lined up at metaphase plate
- anaphase: sister chromatids pulled apart toward centrosomes
- telophase: chromosomes at opposite poles decondense, nuclear envelope forms, mitotic spindle breaks down to form cytoskeleton
explain the process of cytokinesis
- animals: cleavage furrow separates daughter cells
- plants: cell plate separates daughter cells
define the quiescent G0 phase
- reversible state
- cell resides before entering cell cycle
know where the checkpoints in the cell cycle occur and what happens at each checkpoint
- G1: end of G1 phase; checks cell size, enough nutrients, growth factors, and no DNA damage
- G2: before mitosis; checks that DNA replication is complete and there is no damage in replicated DNA
- M: during metaphase; checks that chromosomes are lined up and connected to spindle fibers
describe how cells become cancerous
- problems with genes regulating checkpoints
- causes uncontrolled cell division
- gene mutations build up across many divisions
explain how protooncogenes are normal but become oncogenes
- protooncogenes code for positive cell regulators (tell cell when to go through division)
- mutations make them oncogenes
describe the affect of oncogenes and tumor suppressor genes on the cell cycle
- oncogenes: accelerated cell division because positive cell regulator overrides other processes, accelerates cell growth
- tumor suppressor genes: when mutated they stop negative cell regulators (tell cell to stop division) from working, cell divides even with problems
explain the process of cell division in prokaryotic cells
- binary fission
- bacterial chromosome replicates
- 2 daughter chromosomes move apart
- septum forms and divides the cell
compare and contrast sexual and asexual reproduction
- sexual: creates genetically unique offspring, requires mate and energy, slower population growth
- asexual: creates genetically identical offspring, doesn’t require a mate or energy, faster population growth
compare and contrast mitosis and meiosis
- mitosis: 1 division, genetically identical, 2 diploid cell produced, somatic cells
- meiosis: 2 divisions, genetically unique, 4 haploid cells produced, sex cells
describe the stages of meiosis and the important events that occur at each stage (movement of chromosomes)
- interphase: similar to mitosis
- prophase 1: chromosomes undergo crossing over (exchange genetic information) and associate with homologous pair
- metaphase 1: tetrads line up in metaphase plate randomly (independent assortment)
- anaphase 1: homologous chromosomes separate, sister chromatids remain attached
- telophase 1: sometimes chromosomes recondense, ends with 2 haploid cells
- meiosis 2: similar to mitosis, sister chromatids separate, ends with 4 haploid cells
explain nondisjunction and how it leads to chromosome abnormalities
- when homologous chromosomes or sister chromatids fail to separate during meiosis
- results in duplications or losses of entire chromosomes
explain errors in chromosome structure through duplication, deletion, and structural rearrangements
- duplications: extra copy of small piece of chromosome
- deletions: deletion of a segment of a chromosome
- inversions: detachment, 180-degree rotation, and reattachment of segment of chromosome
- translocations: part of chromosome detaches and reattached to another non-homologous chromosome
understand the relationship between genes, alleles, and loci
- alleles are different versions of the same gene; what alleles you have make up genes
- genes are basic unit of heredity passed from one generation to the next
- loci are locations where a gene is found on a chromosome
explain different types of crosses
- monohybrid: for one trait
- dihybrid: for two traits
- test: to find genotype of dominant expressing parent by crossing with homozygous recessive individual
- reciprocal: traits of male and female switch between crosses
explain a model system
- system of convenient characteristics to study a phenomena
- mendel used pea plants
describe mendel’s experiments
- manually cross pollinated true-breeding parental generations (hybridization)
- let F1 generation (hybrids) self-pollinate and observed characteristics
- looked at multiple discrete characteristics
explain how mendel’s results demonstrated continuous variation and contrast with the idea of discontinuous variation
- i think this question is worded wrong; should be other way around
- continuous: mendel didn’t observe, range of difference, offspring are blend of parents
- discontinuous: medel did observe, one of two distinct characteristics shown in offspring
distinguish between different types of crosses and the annotations used to represent each generation
- P: parental generation, true-breeding parents, homozygous for different traits, manually pollinated
- F1: first filial generation, hybrids, all heterozygous and express dominant trait, self-pollinate
- F2: second filial generation, has all genotypes, 3:1 phenotypic ratio
define trait and distinguish between dominant and recessive
- trait: specific characteristic of an individual
- dominant: fully expressed in phenotype, only one copy needed, PP or Pp
- recessive: non-functional copy, expressed in absence of dominant allele, pp
distinguish between genotype and phenotype
- genotype: genetic makeup; PP, Pp, pp
- phenotype: physical appearance: purple flower, white flower
explain the relationship between genotype and phenotype and how they relate to dominant and recessive
- genotype: genetic makeup, can have dominant or recessive alleles, results in phenotype
- phenotype: physical appearance, caused by genotype and dominant or recessive alleles
use a punnett square the calculate the expected proportion of genotypes and phenotypes in a monohybrid cross
- possible alleles in gametes placed on top and side of square
- combine alleles in each box to get potential offspring genotypes
explain mendel’s law of segregation and how is relates to events of meiosis
- alleles/chromosomes segregate during meiosis
- gametes have equal chance of receiving either allele/chromosomes
- only 1 allele/chromosome is carried in a particular gene: individuals have 2 alleles (1 from each parent)
- occurs during meiosis 1 when homologous chromosomes are segregated into daughter cells
explain mendel’s law of independent assortment and how it relates to events of meiosis
- each pair of alleles/chromosomes segregates autonomously and without influence on other alleles/chromosomes
- random combinations of alleles in gametes
- occurs during meiosis 1 when homologous pairs line up in metaphase plate in random orientations
explain the purpose of a test cross
- determine genotype of dominant expressing parent
- cross with homozygous recessive to see if offspring exhibit recessive trait or not
use probability rules to predict the outcomes of monohybrid and dihybrid crosses
- calculate probabilities of the separate allele combinations
- multiply probabilities together
identify this non-mendelian inheritance pattern: incomplete dominance
- phenotype of F1 hybrids in between phenotypes of parents
- 3 phenotypes usually seen
- blended mix
identify this non-mendelian inheritance pattern: codominance
- 2 dominant alleles affect the phenotype is separate but distinguishable ways
- both phenotypes are seen separately
- human blood type
- unblended mix
identify this non-mendelian inheritance pattern: multiple alleles
- genes with more than 2 alleles
- very common
- each organism can only have 2 alleles
- large variance in phenotypes
- human blood type has 3 alleles
identify this non-mendelian inheritance pattern: sex linkage
- genes on sex chromosomes
- fruit fly eye color
describe the phenotypic outcomes of epistasis
- 9:3:4 ratio
- 9 have black pigment and can deposit
- 3 have brown pigment and can deposit
- 4 can’t deposit pigment (doesn’t matter what the pigment color is)
