Exam 1 Flashcards
What are three types of changes that occur?
Permanent changes; changes that occur normally during development; changes that occur happen in all organisms
What is development concerned with?
Progressive changes that occur during the formation of organisms
Explain permanent changes
Result in formation of specific structures such as the eye, flower, or limb
Describe changes that occur normally during development
Changes are programmed in organisms genome and occur throughout life
Describe changes that occur in all organisms
Changes occur in all organisms not just vertebrae’s includes prokaryotes, bacteria, eukaryotes, fungi, plants, and animals
What are the multiple levels of development
1) genes 2) macromolecules (proteins, lipids)
3) cells, 4) tissues (groups of cells)
5) organs (tissue arrangement)
6) Whole organism itself
What are the six major development questions
1) differentiation
2) morphogenesis/pattern
3) growth
4) reproduction
5) evolution
6) integration of environment
Describe the question of differentiation
How do you have a single cell give rise to whole organisms containing all different cell types multiple cell types from one cell
stem cells, how to get a cell to make a particular cell type
Describe the question of morphogenesis/pattern
Different cell types arrange in patterns
what are the rules that dictate where cells go
Describe the question of growth
Cells divide, increase in size and stop dividing cell size is regulated, what controls this
growth of arm, how some know when to stop dividing
something regulating the growth
uncontrolled cell growth leads to cancer
Describe the question of reproduction
Info set aside very early in development for continuation into next-generation
how do we do this, set info aside?
Describe the question of evolution
Anything that results in phenotype changes in embryo
Darwins finches- all starts with embryo
can be at structural, genetic, or cellular levels
Describe the question of integration of environment
Big impact, why mothers don’t drink, do drugs don’t let kids eat lead paint, can have severe impact on development
What are the six common stages/sequence that occurs during development for life cycles
1) fertilization
2) cleavage
3) gastrulation
4) organogenesis
5) larval stage
6) reproduction
Describe the lifecycle stage of fertilization
Fertilization is when the sperm meets the egg to form a Diploid organism, form unique gene combination, gametes join
Describe the life cycle stage of cleavage
Rapid cell division; single cell organisms ➡️ multiple cellular organism with cleavage
results in a hollow ball of cells known as the blastula
Describe the lifecycle stage of gastrulation
Ball begins to fold in on itself
cells move relative to one another
dimple Inward, cells moving in and the gastrulation leaves the three germ layers
What are the three germ layers
1) endoderm (inside)
2) ectoderm (outside)
3) mesoderm (between)
Describe the lifecycle stage organ formation, organogenesis
Germ layers interacting result in formation of tissue and organs
lots of cell migration -nervous system, somites, muscles
Describe what the germ plasm does
The germplasm stays together localized, as embryo develops it ends up in the gonads goes on to form gametes for next-generation
What is the Phylotypic stage
It is the stage that is common for all animals in a certain phylum
Describe the life cycle larval stage
Immature before they become sexually mature (metamorphosis: frogs, insects)
Describe the lifecycle stage of reproduction
Cytoplasm in egg set aside to form germ cells cytoplasm become cells that have the gametes
What did Von Baer discover?
After the labels of his embryos came off and he couldn’t tell them apart he realized that there must be a similar stage before organism start to develop differently
What did Von Baers realization lead to
Phylotypic- resistant to change genes involved with performing early organs are genes that also have critical functions later in development
What did people used to say that’s not true?
Ontogeny recapitulates phylogeny (development shows what’s happening before evolution)
What is von Baers first law
Phylum characteristics appear before characteristics of more refined groups such as order/class
What is von Baers second law
You see more general characteristics of a group of occur before more specialized characteristics do, ectoderm similar in all vertebrae’s looks same early on then starts to specialize into hair, scales, feathers
What is Von Baers third law
Embryos don’t pass through the adult stages of other species
What is Von Baers fourth law
Embryos are like the embryos of other species not like the adults
Differential gene expression
Nucleus Vs. cytoplasm
different genes expressed in different cell types
What are the four differential gene expression levels
1) can control expression of genes at the transcriptional level, production of mRNA from DNA
2) can regulate at post transcriptional level from DNA once RNAs made you can clip out Introns, splice, and transport, expressing mRNA
can splice in different ways to make different proteins
3) translational control- production of proteins from mRNA, regulate production of proteins from mRNA
4) post translational level- lots of proteins need to be modified before they are functional clipping/grouping/phosphorylation
What is genomic equivalence
Idea that every cell in our body has exactly the same genes
What are genetic switches?
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Give 2 examples of how genetic switches can link developmental changes to evolution
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Describe polytene chromosomes in insects
Total RNA produced by any cell is just a small part of genome, 10% of the genome in 1 cell
What type of cells in insects duplicate their DNA but don’t divide, end up with 100’s of 1000’s of copies of identical DNA in parallel to each other
Salivary glands
What are puff’s?
Swollen puffs, DNA portion found in some of the reproducible banding patterns. They occur at different times and in different cell types
Describe the first amphibian cloning experiment
Done in Indiana (1950) it showed that you could transfer the nucleus from a blastula at put it into a enucleated egg and it would go on to form a tadpole. This would not work if the nucleus was from a cell that had already differentiated.
What got john Gurdon the Nobel prize
He was the first to show that cloning was possible using already differentiated cell nuclei. Using xenopus he took skin from the adult frogs foot and these nuclei when placed in a enucleated cell, produced a tadpole
Describe the 1st mammalian cloning
1990’s dolly the sheep in Scotland. They used 7 different strains of sheep so they could keep track of the donor and recipients. They arrested cells (used mammary gland cells) at the G0 phase. Put these next to occyte(enucleated) and gave them an electric shock which fused them together. They started to develop and then were placed in a pregnant sheeps uterus
What type of cloning was dolly the sheep
Reproductive cloning
What type of cloning is used for humans to help with cell deficits?
Therapeutic cloning
How do we get DNA from blood if red blood cells have no nucleus?
White blood cells along with some other components do contain nuclei and therefore DNA
DNA+protein=
Chromatin
Which has more protein, prokaryotes or eukaryotes?
Eukaryotes
What are most proteins in eukaryotic nuclei?
Histones
What do histones form?
Nucleosome
What is the basic unit of chromatin structure?
Nuclesome
What are histones composed of?
Octomer, 2 dimers H2A and H2B, 2 dimers of H3 and H4 = 8 total
How many Base pairs is a histones DNA strip
140bp’s
How many bp’s is the area of DNA that allows for stabilization?
60bp’s
What keeps the histones from unwrapping
H2
H1 causes the nucleosides to be tightly packed so what cannot or very little can occur?
Transcription
What joins nucleosomes together?
Linker DNA
What are the histones tails used for?
Groups can join to either loosen or tighten the DNA band around the histone core
What does the binding of a acetyl group to a histone tail do?
It loosens the DNA around the core histone which allows for transcription
What does the binding of a methyl group to a histone tail do to a nucleosome?
It causes the DNA to bind more tightly preventing transcription
What is the nucleosome function
90% of genes are inactive due to being tied up in nucleosomes. In order for transcription to start, you need to remove the nucleosomes
????? Check old note cards
