EXAM 3 Flashcards
mendels law of segregation: relation to chromosome movement
-each individual has 2 factors for each trait
-the factors separate during the formation of gametes
-each gamete contains only one factor from each pair of factors
-fertilization gives each new individual two factors for each trait
mendels law of independent assortment: related to chromosome movement
each pair of factors separates independently
-all possible combinations of factors can occur in the gametes
what is an allele? D vs R
an allele is an alternative form of a gene, they occur at the same locus on homologous chromosomes
-dominant allele will mask the expression of the recessive allele
-recessive will only exert its effect in a homozygote
genotype vs phenotype
genotype: alleles the chromosomes carry responsible for the trait (the letters)
phenotype: individual’s actual appearance (effect of letters)
patterns of inheritance: G and P OUTCOMES
homozygous: 2 of same allele
heterozygous: 2 different alleles (recessive allele is masked by dominant)
-homo dom= DOMINANT
-hetero= DOMINANT
-homo recess. = RECESSIVE
2 HETEROZYGOUS CROSSED IN MONOHYBRID =
genotype= 1:2:1, phenotype= 3:1
TEST CROSS = unknown genotype crossed with homo recess.
autosomal dominant vs autosomal recessive
RECESSIVE: most children who are affected have parents who are not affected
-heterozygotes (Aa) have an unaffected phenotype
-2 parents who are affected will always have children who are affected
-close relatives who reproduce are more likely to have children who are affected
DOMINANT: children who are affected will usually have a parent who is affected
-heterozygotes (Aa) are affected
-2 parents who are affected can produce a child who is NOT affected
-2 parents who are UNaffected will NOT have children we are affected
-both males and females are affected with equal frequency
Tay Sacchs
recessive disorder!!
-occurs among jewish people
-lack of enzyme Hex A and subsequent storage of its substrate in lysosomes
-development is slowed down in 4-8 months old causing neurological impairment, psychomotor difficulties, blind, seizures, and paralysis
cystic fibrosis
recessive disorder!!
-most lethal in white people lol
-chloride ions fail to pass thru plasma membrane (lack of water causes mucus in bronchial tubes which interferes with lungs and pancreas
-difficulty breathing and digesting
sickle cell disease
recessive disorder!!
-red blood cells are irregular caused by abnormal hemoglobin
-clog vessels causing poor circulation, anemia
-hemorrhaging leads to jaundice, pain in abdomen and joints, and damage to internal organs
-prevents malaria tho?
huntington disease
dominant disorder!!
-leads to degeneration of brain cells
-caused by mutated copy of huntingtin
-effects in teen years then by 10-15 years death will happen
incomplete dominant vs codominance
incomplete: heterozygous has intermediate phenotype between homozygotes (red flower + white flower = pink flower)
codominance: both alleles are expressed in heterozygous (red flower + white flower = red and white flower)
polygenic inheritance
trait controlled by 2 or more genes
-dominant alleles are additive
-results in continuous variations of phenotype (skin and height)
special characteristics of inheritance for ABO blood types
IA= A anitgen
IB= B antigen
i= neither A or B
-IA and IB are dominant over i
-IA and IB are codominant
BLOOD TYPES
A: IAIA OR IAi
B: IBIB or IBi
AB: IAIB
O: ii
environment vs genetic trait
nutrition and temperature can influence genetic trait
ex: height influenced by nutrition
-temp of egg incubation determines sex
-himalayan rabbit produces melanin only at low temp
why might scientists determine if a trait is strongly affected by environment
the argument nature vs nurture!!
-identical twins live in different environment and both contain same trait, then its genetics
-behavioral traits are partly heritable
on the other hand, if you have a genetic disorder, changing diet can minimize effect of the disease
linked genes
genes inherited together
DO NOT SHOW INDEPENDENT ASSORTMENT because linked alleles are all on one chromosome and are inherited together
-crossing over between non sister chromatids on homo chrom.
-22 autosomes and 1 pair of sex chrom
X linked inheritance
male receives X-linked allele from mother’s X chromosome
phenotype and genotype predictions based on sex linked traits
A Homozygous man X hetero (carrier) woman will give the sons a 50% chance of being affected and the daughters a 50% chance of being a carrier (but wont be affected)
x-linked recessive = more men than woman affected because recessive alleles on X chrom are always expressed in guys
x-linked dominant = affected males only pass down to daughters who have 100% chance of being affected
duchenne muscular distrophy
x-linked recessive!!
-wasting away of muscles, absence of protein
-waddling gait, toe walking, frequent falls, difficulty rising, muscle weakness,
-death by 20, males are rarely fathers
-proteins remains by passing from carrier mom to daughter
hemophilia
x-linked recessive!!
-affected persons blood does not clot, bleed internally around joints
-can be stopped by transfusions of blood/plasma
Hemo. A = absence of clotting factor VIII
Hemo. B = absence of clotting factor IX
how do chromosomes disorders arise
NONDISJUNCTION!!
failure of homo chrom. or sister chromatids to separate during either mitosis or meiosis, produces cells with abnormal chromosomes
trisomy: extra chromosome
monosomy: one less chromosome
down syndrome
autosomal trisomy!!
short stature, eye lid fold, flat face, stubby fingers, large fissured tongue, mental impairment
-happens by nondisjunction of an extra copy of chromosome 21
-chances of having a kid with zds increases at the age of 40
turner syndrome
-only 1 chromosome (X)
-short with webbed neck, high palate, small jaw
-congenital heart and kidney defects
-ovarian failure and do not undergo puberty
-NO mental impairment, can live healthy life
klinefelter syndrome
male has 2 or more x chromosomes in addition to the Y
-extra X is called Barr body
-testes and prostate gland are underdeveloped
-breasts, large hands and feet, slow to learn, increased chance of lupus and breast cancer
poly-x females
more than 2 x chromosomes in females
-tall and thin
-possibility of menstrual difficulties but most are fertile
-more than 3 x chromosomes = intellectual disabilities
chromosomal deletion
chromosome loses an end piece due to break
chromosomal duplication
chromosome segment occurs more than once
chromosomal translocation
movement of one chromosome segment from one chromosome to another
extra material from one, missing material fro another (abnormalities)
chromosomal inversion
segment of chromosome is turned 180 degrees (opposite)
List two observations Darwin made on his voyage that influenced the development of his theory
He visited tropical rainforests and other new habitats where he saw many plants and animals he had never seen before (see Figure below). This impressed him with the great diversity of life
-He dug up fossils of gigantic extinct mammals, such as the ground sloth (see Figure below). This was hard evidence that organisms looked very different in the past. It suggested that living things—like Earth’s surface—change over time.
Compare and contrast Darwin’s and Lamarck’s explanations as to how evolution might happen
Lamarck: acquired characteristics- environment can bring about inherited change
ex: giraffe with short necks stretch out their necks to eat leaves, so offspring have longer necks (NO EVIDENCE FOUND FOR THIS LOL)
Darwin: natural selection- traits with an advantage are passed down in fertile offspring
ex: giraffes with already taller necks survive while shorter necks die making taller gene last longer in giraffe population
Describe how theory on natural selections suggests how evolution might work
-individual organisms within a species exhibit variation that can be passed down from generation to the next (variation must be heritable)
-organisms compete for available resources
-individual organisms within a population differ in terms of reproductive success (more energy = more reproductivity)
-organisms become adapted to conditions as the environment changes
biological evolution
all the changes that have occurred due to reproductive success in living organisms over geological time
fossil evidence for evolution
FOSSIL (remains and traces of past life)
-hard body parts most often preserved (bone, teeth, pollen, wood, shells)
-majority embedded in sedimentary rock and deposited in layers called strata (younger on top, older on bottom)
mold: harded rock with air space
cast: silica fills that space
five conditions necessary for the allele frequencies in a population to be in Hardy-Weinberg equilibrium.
- no mutation
- no genetic drift
- no gene flow
- random mating
- no selection
Calculate the genotypic frequencies for a population
just do the math emma
five forms of microevolution
mutations: alteration in allele frequency in a population
-w/o it there would be no inheritable diversity, are random!!
genetic drift: chance events that change allele frequency from one generation to the next
-bottle neck effect: catastrophes like hurricanes and volcanoes that kill off a lot of individuals
-founder effect: few individuals colonize on an island or new habitat (birds going from forest to the beach)
gene flow: movement of alleles between a population
-Individuals or their gametes migrate from one population to another and breed in the new population
-gene flow increases diversity
nonrandom mating: individuals are selective about who their mate is
natural selection: fitness (ability of organism to reproduce fertile offspring)
each type of microevolution & Define heterozygote advantage and give an example
stabilizing selection: against extreme phenotype for average (tigers cant have long tails bc they will trip, tigers cant have short tails because they will lose balance, so medium works)
directional selection: extreme phenotype is favored!!! long tails for lizards make it look like a snake so they stay alive from predators
disruptive selection: both extreme phenotypes work but not average (long squirrel tail good for intimidation, short squirrel tail good from running, medium does not do anything
heterozygote advantage: only alleles that are expressed are subject to natural selection
example: recessive dies due to malaria, hetero isn’t affected by any, dominant dies due to sickle cell
various forms of species isolating mechanisms
habitat isolation: separated by location (snakes in water can’t mate with snakes on land)
temporal isolation: breeding at different times or seasons (skunk breeds in fall, another breeds in winter)
behavioral isolation: different courtship rituals (bluefoot boobies do a lil dancy dance while masked boobies practically makeout)
mechanical isolation: physical incompatibility (penis does not fit vag)
gametic isolation: molecular incompatibility of sperm and eggs
the processes, including examples, by which speciation can occur.
allopatric speciation: geographical barriers separate a population into 2 groups (dam)
sympatric speciation: speciation occurs in same region, but just isolate themselves
adaptive radiation: one species becomes many through natural selection
-galapagos finches reproduced and ended up in all areas of islands
-different beaks due to different food sources
how phylogenetics, the theory of evolution, and classification of organisms are interrelated.
phylogenetics: study of evolutionary relatedness of groups of organisms
phylogeny: hypothesis of evolutionary relatedness among taxa (group of shared traits) represented by tree
biogeographical evidence for evolution
forms evolved into one large locale then spread to accessible regions causing a mix in different plant and animal species
continental drift: movement of earths crust through tectonic plates causing the movement of continents
also caused mass extinction of certain plants and animals
anatomical evidence for evolution
homologous structures: similar in different types of organisms because they descended from the same ancestor
analogous structures: similar in function BUT differs in anatomy and was evolved separately (eyes of octopus and eyes of human, same function but we aren’t related)
transitional structure: a structure that was functional to the ancestor but serves no use now (whales still have a pelvis because at one point they walked on land even tho they dont now)
vestigial: one function in one group but no purpose in closely related group (pelvis irrelevant to snakes, we use pelvis for birth and movement)
biochemical evidence for evolution
all living organisms contain DNA, ATP, have the same triplet code for 20 amino acids, enzymes,
Describe contributions of Leeuwenhoek and Pasteur to the science of microbiology.
Leeuwenhoek: discovered one of the first lenses to view microscopic forms
-believe these life forms can evolve from spontaneous matter
Pasteur: 1st experiment was boiling sterilized broth and creating microbial air
-concluded there was something smaller than bacteria, VIRUSES, created vaccine
Explain what is meant by the term microbiota.
typical complement of bacterial species found on the human body
unaware of their presence, but have beneficial effects
Give examples of beneficial effects of microbes.
bacteria on skin helps crowd out harmful microbes
-bacteria in intestines aids in digestion and making vitamin K and B12
Distinguish between chemical and biological evolution.
CHEMICAL= early earth, inorganic chemicals (capture energy), small organic molecules (polymerization), polymers
BIO= (plasma membrane) protocell, (origin of genetic code) cell,
cell goes into to 1st self replication, LUCA which is the common ancestor for all life, extant organisms
List and describe the four stages that are thought to have led to the formation of cells.
stage 1: organic monomers
-simple organic molecules evolved from inorganic compounds (amino acids, nucleotides)
stage 2: organic polymers
-monomers joined to make polymers (DNA, RNA, proteins)
stage 3: protobionts
-polymers enclosed in membrane to form first cell precursor
stage 4: living cells
-protobionts acquired self replication, and other cell properties
Explain the methods and significance of the Miller-Urey experiment.
purpose was to test that amino acids could have derived from natural chemical reactions in young earth
-amino acids formed from ammonia, nitrogen, CO2, CO, methane, water, and H2 in earths atmosphere
List some of the major characteristics used to distinguish Archaea, Bacteria, and Eukaryotes.
Archaea: genome is single, closed, circular DNA molecule
-plasma membrane with a single lipid layer
-methionine is at start of protein synthesis
-no nucleus or organelles and has histones!!
Eukaryotes: has nucleus and organelles, histones and introns,
-methionine is at start of protein synthesis
Bacteria: lacks nucleus and membrane bound organelles in cytoplasm
.2-10 um in size
Distinguish between halophiles, thermoacidophiles, and methanogens.
halophiles: salty habitats
-isolated from environment such as great salt lake, dead sea
thermoacidophile: extremely hot, acidic, aquatic
-hot springs, geysers, underwater volcanoes
-evolved to function at temperatures at 80C
methanogens: use CO2 and hydrogen as energy sources
-produce methane
-in anaerobic environments like swamps, and intestines of animals (cows, humans)
Identify the major structural features of bacteria
flagella: in motile bacteria to help move
fimbriae: used to bind to surfaces
storage granule: singular chromosome
plasmids: accessory rings of DNA that carry out genes
Describe bacterial reproduction
reproduce asexually through binary fission (bacterial cell replicates its new genomend divides into 2 daughter cells)
can form resistant endospores (protects DNA from environment stress)
Describe the three ways bacterial can increase their genetic variation.
conjugation: transfer of genetic material from one cell to another (donor cell passes DNA to recipient through sex plius)
transformation: bacterium taking up extraneous genetic material from the environment by dead bacteria
transduction: viruses carry bacterial DNA from cell to cell
Describe the metabolism and ecological function of Cyanobacteria
cyanobacteria are photoautotrophs (have chlorophyll and do photosynthesis to release oxygen)
-symbiotic relationship with lichens (lichens provide place to grow and obtain minerals)
-camouflage sloths?
Describe diseases caused by Streptococcus pyogenes and Staphylococcus aureus
STREPTOCOCCUS PYOGENES
-pharyngitis: strep
-impetigo: skin disease
-scarlet fever: produces red rash
-rheumatic fever: auto immune, causes heart damage, caused by untreated strep throat
STAPHYLOCOCCUS AUREUS
20% ppl are carriers
skin infections
strain resistant to methicillin is MRSA (kills young healthy, has gene for toxins)
-tuberculosis: lung infection
Describe the different types of food poisoning and list two species that cause them
produces toxins while they are growing in food
-vomiting and diarrhea
-clostridium botulinum (produces one of the most toxic substances on earth)
-beauty?
cause infection while growing in intestines
-salmonella causes symptoms after several days of growing
Describe the function of most antibiotics
inhibit bacteria by interfering with a unique metabolic pathway of bacteria
-NOT EXPECTED TO HARM HUMAN CELLS
either inhibit protein synthesis by bacteria (erythromycin and tetracyclines)
OR inhibit cell wall biosynthesis (penicillins and cephalosporins)
Describe the pro’s and con’s of the popular usage of probiotics
Pro: stops the bacteria from interfering with metabolic pathways (AKA less sick yayyy)
Cons: potentially fatal allergic reactions
-killing off normal flora (beneficial bacteria)
-overgrowth of harmful bacteria in intestines and vagina
-strains evolved to be resistant to antibiotics
MRSA and tuberculosis have antibiotic resistance
Distinguish between viruses and prions
viruses: acellular structures that are parasites
-use the host cell’s replication machinery (ribosomes and enzymes)
-capsid: outer portion made of proteins, surrounded by lipid envelope, spikes for attachment
-nucleic acid core (DNA , RNA)
-can be spherical, helice, or polyhedron
prions: protein infectious particles
-causes normal proteins change their shape,
-degenerative diseases in nervous system
-prions through ingestion of infected tissues
List and describe the stages of viral reproduction for a rubella virus
- attachment: spikes of virus bind to a receptor molecule on host cell (virus hijacks it)
- entry: viral envelope fuses with host’s plasma membrane and rest of virus enters cell
-uncoating: genome is freed when cellular enzymes remove the capsid - replication: viral enzyme makes complementary copies of the RNA genome
- biosynthesis: RNA molecules serve as mRNA for the production of more capsid and spike proteins using ribosomes
- Assembly: capsid forms around copy of viral genome
- budding: new viruses are released from cell surface (acquires envelope and spikes)
Describe antigenic drift and shift.
DRIFT: minor genetic mutations (common cold and flu
-mutations lead to modified spike
SHIFT: major changes take place on surface antigens as genome are reassorted between 2 flu viruses that infect the same cell (2 viruses combine into 1)
List several prions and the species they infect
Bovine spongiform encephalopathy or mad cow disease,
chronic waste disease in deer elk moose
scrapie: sheep scratch off wool
Summarize what is known about the evolution and characteristics of the first eukaryotic cells
first eukaryotic cell arose from prokaryotic cell
-mitochondria resulted from nucleated engulfed aerobic bacteria, chloroplasts originated from mitochondria engulfed cyanobacteria
ENDOSYMBIOSIS
Describe the general characteristics of a protist.
eukaryotes
-very diverse
multicellular, unicellular
have meiosis and sex (universal to eukarya)
have mitochondria (universal to eukarya)
Describe the ways protists can obtain food and energy
photoautotrophs: aka algae, produce food by photosynthesis
heterotrophs: aka protozoans, eat bacteria and other protists
heterotrophs: aka parasites, derive nutrition from living host, harmed by interaction
mixotrophs: use photosynthesis and heterotrophy
Describe the basic characteristics of the protist supergroups
Archaeplastida: land plants, green and red algae
Chromalveolata: brown algae, diatoms , ciliates, sporozoans, and water molds
Excavata: euglenids, flagellates
Amoebozoa: amoeboids, plasmodial and cellular slime molds
Opisthokonts: animals, fungi, flagellates
List the characteristics of Spirogyra.
Archaeplastida
charophyte
filamentous green algae (cell has ribbon like chloroplast)
sexual reproduction by conjugation(cell wall connect by tube and haploid cells fuse)
excavata flagellates
most are heterotrophic protozoans that propel themselves using one or more flagella
List the characteristics of Euglena
feeding groove
-have flagella
-photosynthesis
-mixotrophy
-eye spot for detecting light intesity
List the characters tics of Amoeba and Plasmodial Slime molds
Amoeba – organisms with pseudopodia
-feed by phagocytosis
Plasmodial Slime Molds
-single cell
-large and multinucleated
-feed on decomposers on dead plant matter
-fruiting bodies: spores release amoebae
LIFE CYCLE
Diploid multinucleate plasmodium.
Plasmodium develops many sporangia during unfavorable conditions
The spores survive until moist and able to germinate
Spores release haploid amoebae
Haploid amoebae eat decomposers and reproduce or act as gametes and fuse
List the characteristics of the fungi we covered in class.
release enzymes into their environment, digest food outside of body, and absorb digested food
-some are parasitic and some are saprophytic decomposers(ecycle inorganic nutrients from environment)
Describe the symbiotic relationships of fungi with other organisms including mycorrhizal relationships and lichens
lichens: associations between fungi and cyanobacteria algae
-efficient at acquiring nutrients and moisture
-poor soil, rocky
-primary colonizers bc produce organic material for plants
mycorrhizae: relationship with plant roots
-allow plants to grow in poor soil
-plants give products of photosynthesis for fungi
-fungus gives minerals to roots
-almost all plants have this relationship
diatoms
unicellular algae, glassy cell wall made from silica, freshwater marine
brown algae
chromalveolate
multicellular algae, brown because pigments, kelp (attached to seafloor), primary producers
dinoflagellates
chromalveolate
unicellular algae
-cause blooms in polluted coastal waters
-red rides
-bioluminescent ocean
ciliates
chromalveolate
unicellular protists including heterotrophs
-named for their use of cilia to move and sweep food into their mouth
hyphae
Body a mass of individual filaments in fungi
mycelium
mass of hyphae
Hyphae give the mycelium a large surface area to facilitate absorption of nutrients
ascomycetes sac fungi
cup like structure for reproduction (ascocarp)
truffles, cup fungi, and morels
-reproduce by producing chains of asexual spores called conidia (molds)
ex: penicillium
aspergillus (citric acid)
yeasts: unicellular fungi, wine and beer
basidiomycetes club fungi
sexual reproduction through basidium (edible part of mushroom is basidiocarp
. In which kind of cross could you expect to find ratios of 1:1:1:1 among the offspring
two trait test cross
. What genetic disorder is associated with the lack of an enzyme necessary for the normal metabolism of the amino acid phenylalanine?
PKU
What are the chances that two individuals with wavy hair (an incomplete trait) will have a curly-haired child? Curly hair and straight hair exhibit incomplete dominance
25%
When two or more genes with multiple alleles affect the same trait in an additive fashion, it is termed
polygenic inheritance
A color-blind (recessive trait) woman will pass the allele
to all their children
Generally, it is not possible to determine whether nondisjunction failed to occur in oogenesis or spermatogenesis. However, it is possible to assert that _____ resulted in nondisjunction
XYY, spermatogenesis
All cases of Down syndrome are caused by trisomy of chromosome 21.
false
What evidence would NOT be studied by a biogeographer
the genetic makeup of organisms that evolved in separate but similar conditions
Which of these conditions is NOT among the requirements of the Hardy-Weinberg equilibrium?
small pop with genetic drift
Which of the following kinds of molecules is thought to have been absent from the primitive reducing atmosphere
oxygen
- Which of these is a correct description of a form of horizontal gene transfer in bacteria?
conjugation
Which of the following is NOT true about viruses?
They contain nucleic acid, protein, and mitochondria.
The first membranes that formed before full cells were likely made of
fatty acids
Which features set most of the members of protista apart from the rest of the kingdoms
unicellular and microscopic
Which is an example of an alga
diatoms
At one time, biologists thought that fungi were merely forms of plants that had lost their chlorophyll and had returned to saprotrophy to gain food. Why is this no longer considered a solid theory?
fungi have cell walls made of chitin
Amoebae
have a nucleus, are heterotroph, have pseudopods
