Biology Final Exam Unit 1 Development What does DNA have to do to for a cell to divide Unzips polymerase replicates by attaching complementary pairs Semi conservative replication Mitosis produces two identical daughter cells DNA wrapped around histones Functions of cell division Asexual reproduction Repair Growth Replace worn cells Multicellular organisms different types Chromosome to different cells Cell cycle Starts as one cell becomes complex Mitosis produces genetically identical cells but how do we get Centromere is the middle part of the X Sister chromatids are each side of the X They re genetically identical and are separated during mitosis and go Duplicating DNA happens in S phase Mitosis Microtubules contract and pull chromatids apart by a motor protein at the centromere chewing it up as it goes Phases of mitosis Interphase G1 S G2 DNA loose in cell Prophase chromosomes begin to coil centrioles begin to separate the cell Pro metaphase chromosomes move toward the center of Metaphase chromosomes lines up in middle of cell Anaphase sister chromatids separate key event in mitosis Telophase cell splitting in two nuclear membrane reforms MPF is cyclin and CDK Cyclin MPF mitosis breaks down CDK CDK cyclin dependent kinase When cyclin reaches a critical concentration it binds with CDK making Negative feedback MPF Mitosis breaks down cyclin Fungal development nutrients Slime molds Large multicellular bodies that grow into environment and absorb Fungus like Start as single cells and when they re starved the aggregate and firm one big slug like structure They grow a stalk and capsule Plant development Plants have no developmental endpoint Root and shoot They are modular organisms and continually divide Meristems are the source of new cells Root meristem is the root cap because it has to push through the ground Stem meristem is more complicated They have leaves which also have bits of meristem that can grow new leaves and branches Every cell does not have the same phenotype because of gene More complex in eukaryotes because there are more possibilities for Gene expression expression control Anabolic pathway Tryptophan Tryptophan absent repressor inactive operon is on RNA transcribed Tryptophan present repressor active RNA polymerase can t bind and no transcription occurs Protein is inactive repressor Catabolic pathway Lac operon Protein is made in the active form and binds to operator The RNA polymerase can t bind and no transcription occurs If allolactose binds to repressor it becomes inactive and transcription occurs Chromatin DNA and histones Can be modified Acetylation acetyl groups attach to histones they repel each other and spread out Methylation methyl groups attach to DNA no transcription occurs can be passed to offspring Exon contains info for coding protein Intron will be spliced out Enhancer pieces of DNA that activators can bind to starts interacting bends and Cells are different because of different activators because that means different allows RNA synthesis to start genes are being transcribed Cytoplasmic determinants Made my mother when she makes the egg Not evenly spread out in the egg When the cells divide more of one molecule ends up in each new egg Determination vs Differentiation Determination cells fate is set it will go down a specific pathway that won t change Differentiation when all cells don t look alike muscle cell vs muscle cell they are differentiated They have a specific form and function Determination occurs before differentiation Formation of muscle cells Embryonic precursor cell can become anything Master regulatory gene gets turned on and makes protein Determination occurs when the master regulatory gene makes transcription factors Formation of a body The egg only contains one cell that becomes the organism The other cells are there to nurture the egg Parts of the fly are in the same places as in the larvae Arthropoda are segmented animals they figure out which end is which and begin developing Antenna paideia Legs for antennae Legs are appendages Inappropriate set of genes turned on Hox genes places Genes that control formation of appropriate structures in the right Many animals have the same hox genes They re in the same order on chromosome as they are in the body Vertebrates can have multiple copies of genes which can free up genes and is why they re so complex Bicoid Cytoplasmic determinant A gene in flies Biocides mutant is a two tailed fly makes a non functional version of the protein There is no signal that says make head here Ways cell growth can be uncontrolled DNA next to new promoter results in excess growth Gene amplification whole gene is compiled multiple items and control of amount of expression is lost Point mutation can occur within a controlled element mutation in controlled region or within the gene protein is resistant to breakdown and lasts longer Fertilization Sperm is a way to move the nucleus Head contains nucleus Acrosome is to get the nucleus into the egg Mitochondria is for energy to swim Contact sperm digest jelly coat Acrosomal reaction Ejects Acrosomal process Recognition protein receptors in egg bind to Acrosomal process Egg receptors and Acrosomal proteins are species specific Egg membrane depolarized Fast block of polyspermy Cell membranes fuse Sperm nucleus enters egg Cortical reaction Ca wave stimulates release of cortical enzymes out of cell and the cell membrane pulls away from vitelline layer Slow block when fertilization envelope hardens Jelly layer pulls away when cortical come out Rapid series of mitotic cell division No cell growth Pattern of cleavage is species specific and critical to Cleavage normal development because cleavage partitions maternal cytoplasmic determinants Protosomes Mollusks Arthropods worms snails crustaceans Spiral an determinate at the eight cell stage Offset from cleavage If you cut embryo in half it would die because fate is determined Deuterosomes Echinoderms chordates Starfish and people Radial and indeterminate at the eight cell stage Cleavage axis produces aligned cells Could be cut in half and would not die because cells aren t determined Blastula A hollow ball of cells after the morula grows The cavity is called a blastocoel Each cell is a blastomere Microlecithal little yolk Holoblastic each cell divides completely Sea urchin Frog Mesolecithal more yolk than sea urchin Polar due to uneven yolk Animal pole is mostly cytoplasm Vegetal pole is mostly dense yolk Holoblastic
View Full Document
Unlocking...