Test 1- Fundamental properties of living organisms:o Evolution – all life has a common ancestor; traits are passed on but change over time; our common ancestor had DNAo Structure and Function – mitochondria is a highly folded membrane to increase surface area and cellular respiration; more surface area = more ATPo Reproduction and Inheritance – DNA has the properties- Functions of cell division:o Reproduction – 1 parent splits in 2o Growth and development – all cells divide over and overo Repair and maintenance – cells die; injury- Stages of Mitosis:o Interphase o Prophase – centrioles migrate to opposite sides; DNA condenses’ nuclear membrane breaks downo Prometaphaseo Metaphase – chromosomes line up in the middleo Anaphase – sister chromatids split in 2; are pulled apart by microtubuleso Telophase – strands uncoil and cell divides- Mitosis is part of a Cell Cycle (stages of the cycle):o Interphase – everything outside of mitosis; contains G1, S, & G2o G1 – growth and does whatever its job iso G1 checkpoint – big stopping point for a lot of cellso S – DNA gets copiedo G2 – does its job; growtho G2 checkpoint – causes cells to move into mitosiso Mitosiso M checkpoint – cell can stop or keep going- Chromosomes exist as homologous pairs in diploids- Meiosis produces haploid daughter cells from diploid parentso Diploid cell – pairs of homologous chromosomeso Each chromosome – 2 chromatidso Homologous chromosomes – same set of genes but not necessarily the same code (brown/blue eyes)o Sister chromatids – code for genes is exactly the same on each sideo Diploid – 6 chromosomes; homologs are in a pairo Haploid – 3 chromosomes; only one of each homolog- Meiosis I (Anaphase I) separates homologous chromosomeso Prophase I – homologous pairs attach; crossing over happens here- Meiosis II (Anaphase II) separates sister chromatidso Produces 4 haploid cells b/c homologs attach- Meiosis produces variation through random segregation of chromosomes- Meiosis increases variation through crossing over during synapsisat the chiasma- Law of Segregation:o Alleles segregate and one gets passes ono 3:1 phenotypic ratio (3 Purple, 1 White)o 1:2:1 genotypic ratio (PP, Pp, Pp, pp)- Law of Independent Assortment:o Dihybrid crosso Round/wrinkled/yellow/green exampleo Each pair of alleles segregates independently of the other pair of alleles during gamete formation- Mendel’s hypothesis – particulate inheritance – genes are passedon but stay as a particular unit- How meiosis relates to the Law of Independent Assortment:o Chromosomes can combine randomly and produce many different combinations in the offspringo It applies to genes located on chromosomes that not homologs. Genes located near each other on the same chromosome tend to be inherited together- Sum Rule:o If the word “or” occurs in the statement, the probabilities are added- Product Rule:o If a statement contains the word ‘and”, the probabilities are multiplied- Patterns of inheritance with Incomplete Dominance:o Both alleles are expressed to give an intermediate form between homozygoteso Codominance – both alleles are expressed to give a different phenotype than either homozygote- Pattern of inheritance for a dominant trait in a pedigree:o Trait is passed directly from parent to child – usually ½o If you have the allele one of your parents has it too- Pattern of inheritance for a recessive trait in a pedigree:o If allele is recessive almost all the copies in the population will be heterozygoteso They are the “carriers”- Patterns of inheritance with multiple alleles:o Multi-locus Inheritance – some traits are determined by more than one locuso Additive Inheritance (incomplete dominance over many loci) – overall affect done by adding up all results; height is affected by many genes- Genetic test crosses can reveal the location of genes on particular chromosomeso Test cross with the recessive!- Loci on the same chromosome are said to be linked and may not be inherited independentlyo Parental linkage – individual/chromosome has the genotype or phenotype of the parental generationo Recombinant – individual/chromosome has a different combination of alleles/phenotypes than the parental typesTest 2- The development in plants is an ongoing process- Meristems are sites of cell division and development follows- Genes can be controlled at multiple stages in gene transcription – DNA methylation, transcription, RNA modification, RNA transport, translation- Methylation – attachment of methyl groups to the DNA; makes the DNA permanently not able to transcribe- Control of transcription occurs through the binding of activators or repressors to special sites on the DNAo Exons get translatedo Introns get spliced out- Cell differentiation occurs during early development because of different concentrations of cytoplasmic determinants (mother provides the CDs)o Determined – set on a pathway to become something, but no change in phenotype yeto Differentiation – cell has taken on a specialized phenotype; control genes are expressed- The earliest genes expressed determine axis polarity (bicoid), followed by organization into body regions (Hox Genes)o Bicoid is a CD- Development consists of fertilization, cleavage, gastrulation, and organogenesis- Cleavage has different patterns in different organismso Rapid series of mitotic cell divisions that occur in the absence of cell growth; the whole thing stays the same sizeand the individual cells divide and get smallero 2 groups – protostomes and deuterostomeso Protostomes have spiral and determinate cleavageo Deuterostomes have radial and indeterminate cleavage- Gastrulation is the folding in of the blastula on itselfo Sea urchin is microlecithal and holoblastico Frog is mesolecithal and holoblastico Chick egg is macrolecithal and meroblastic- Gastrulation produces three basic types of embryonic cellso Microlecithal – small yolko Mesolecithal – moderate yolko Macrolecithal – large yolk- An important example of organogenesis is neurulation, the formation of the embryonic nervous system- Experiments have demonstrated that certain areas of embryos provide positional informationo Gray crescent – forms the dorsal regiono Zone of polarizing activity – ZPA – cells at the top and bottom; weak dosage; sets up anterior/posterior axis of limbo Apical epidermal ridge – AER – cells at the end of the wing; strong dosage; sets up
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