Genetics Exam 1
Terms
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- Gene
- segment of DNA codes for production of a protein
- Allele
- variant of a gene
- Sickle Cell Anemia
- caused by a mutated gene codes for a component of hemoglobin
- DNA
- deoxyribonucleic acid; ATGC double stranded deoxyribose sugar (found in nucleus and mitochondria)
- RNA
- intermediary between genes & proteins AUGC single stranded ribose sugar
- DNA & RNA contain info for building......
- proteins
- Chromosomes
- long strand of DNA & proteins each chromosome contains many genes humans have 46 in all cells except sex cells 23 each from mom & dad
- Genome
- all genes in cells of a particular type of organism 30,000 genes in human genome
- Genotype
- alleles an organism contains
- phenotype
- how the alleles are expressed
- Karyotype
- displays chromosome pairs (except sex) in size order
- Mendelian traits
- gregor mendel single gene causes specific disease
- examples of mendelian traits
- sickel cell cystic fibrosis hemophilia
- Most traits are.....
- non mendelian
- Types of Multifactorial traits
- height diet exposure to chemicals stress illness hair color breast cancer diabetes
- Multifactorial traits
- caused by one or more genes & the environment wide range of phenotypes
- Breast Cancer
- environment plays important role genetic factors: BRCA 1 & 2
- Reduce breast cancer risk by:
- having a low fat & fiber diet & excercise
- Absolute risk
- probability that an indiviudal will develop a particular condition
- Relative risk
- probability that an individual will develop a condition relative to another population (>1 means greater probability than population)
- Risk factor
- threatening situation
- Transgenic
- genes from 1 species put into another ex) tomato w/ fish genes
- Biodiversity
- over a million different species
- Macromolecules:
- proteins carbs lipids nucleic acids
- Proteins
- Structure=function enzymes that speed up reactions provide stuctural support control gene expression (turn genes on & off) very structurally diverse & specific shape 100,000+
- Prions
- Proteins that "go bad" rogue proteins diseases caused by proteins with a bad structure can turn other proteins into prions
- examples of prions
- mad cow disease chronic wasting disease
- Carbs
- Sugars provide energy for cell metabolism provide structural support provide cell identity allows immune system to recognize invadors
- Simple carbs
- individual glucose library
- Complex carbs
- chains of glucose ex) starch used for energy like in a potatoe
- structural carbs
- long chain of glucose molecules with a different bond ex) cellulose that cant be broken down & digested (fiber)
- Lipids
- fats provide energy (way more than carbs or proteins) main component of cell membranes
- Lipid hormone examples
- estrogen, progestin, testosterone
- Nucleic acids
- the genetic material energy source (ATP)
- Nucleus
- where DNA is housed has pores all over the surface allows RNA outside the nucleus gives directions to ribosomes movement in & out occurs through pores
- When MRNA leaves the nucleus it travels....
- to the Endoplasmic Reticulum
- Endoplasmic Reticulum
- bound ribosomes make proteins that export them out of cell
- Rough ER
- site of protein synthesis for export out of cell
- Smoothe ER
- detoxify toxins
- What part of the body has a lot of smoothe ER?
- the liver
- If you get in an accident and take pain meds, (blank) will be in the liver
- smoothe ER
- Golgi Apparatus
- identifies the protein received from the rough ER & ships it
- Lysosomes
- contain digestive enzymes that breakdown cellular material & worn out organelles
- Peroxisomes
- make bile for fat digestion in fireflies, peroxisomes help them "light up"
- Mitochondria
- transformation of food energy to ATP energy DNA is maternally inherited muscles, stomach, & brain have a lot of mitochondria
- Cytoskeleton
- maintains cell shape & structure helps move substances around cell (traintracks) involved in division of cells
- Cancer
- uncontrolled cell division dividing cells use cytoskeleton to move chromosomes apart if cytoskeleton is disrupted, cell cannot divide weakened cytosplasm lets cells not divide as rapidly but also prevents normal non cancerous cells from dividing
- Cell Membrane
- made of phospholipids and proteins proteins provide ion channels to pass through controls movement of substances in & out of cell keeps inside in & outside, but allows certain molecules to pass through
- ions must pass through (blank) to get through the cell membrane
- channel proteins
- HPP & abnormal Na+ channels
- (genetic disease from faulty ion channels) disrupt muscle function & may lead to paralysis
- Prophase
- chromosomes are not lined up
- Metaphase
- line up in middle
- Anaphase
- physically pull apart (centromere breaks) two chromatids separate
- Telophase
- Chromosomes relax & not visible 2 identical cells
- Mitosis
- PPMAT cell division for growth, repair cloning 1 (2n) diploid cell ---> 2 (2n) diploid cells (cloning)
- Meiosis
- cell division for sexual reproduction occurs in eggs & testes creates genetic variation meiosis is cell division for sexual reproduction diploid cell (2n) ---> 4 haploid cells (1n) generates diversity each daughter cell
- Telomeres
- tips of chromosomes are degraded w/ each mitosis
- If telomere doesnt degrade, what will happen?
- the cell will keep replicating (type of cancer)
- Apoptosis
- programmed cell death
- Meiosis 1
- like 2 rounds of mitosis 2n-->1n occurs reduces ploidy leven & separates homologous chromosomes reduction division
- Homologous chromosomes
- humans have 23 sets chromosomes with the same size, shape, & linear arrangement of genes may have different alleles
- Sister Chromatids
- genetically identical
- Prophase 1
- Synapsis occurs crossing over may occur chromosomes condense P1 is how a cell keeps track of homologous chromosomes
- Synapsis
- homologues physically connect occurs in P1 unique to meiosis
- Crossing over
- produces genetic diversity occurs between non-sister chromatids recombines genetic info sister chromosomes & centromeres remain intact anaphase separates the homologous chromosomes
- Independent assortment
- non-homologous chromosomes separate during meiosis (m1)
- When does independent assortment occur?
- metaphase 1
- When a cell with 4 chromosome pairs goes through meiosis, how many chromosome arrangements are possible?
- 2^n 2^4 = 16
- When do gametes mature into sperm & eggs?
- after meiosis
- Spermatogenesis
- process of creating sperm
- Spermatogonium
- (2n) precursor to sperm cells
- Primary spermatocyte
- (2n) meiosis1 occurs secondary spermatocyte is produced
- Secondary spermatocyte
- (1n) meiosis 2 takes place spermatid forms
- Spermatid
- formed from 2ndary spermatocyte (1n) haploid
- Mitosis clones
- 2n-->2n
- Meiosis reduces
- 2n-->1n
- What are sperm made of
- nucleus mitochondria acrosome which is a digestive enzyme to enter egg
- Oogenesis
- process of creating an egg
- Oogonium
- 2n precursor to egg cells
- Primary oocyte
- 2n undergoes meiosis 1 secondary oocyte & polar body are formed
- Secondary oocyte
- 1n undergoes meiosis 2 ovum & polar body are formed
- Ovum & polar body
- 1n formed from secondary oocyte
- Sperm turns diploid egg into
- a haploid zygote
- Fertilization, then (blank), then (blank)
- fertilization then meiosis then mitosis
- Capacitation
- egg secretes an attractant
- Acrosome
- secretes digestive enzymes
- 2 nuclei fuse to form (blank)?
- a zygote
- A zygote divides by (blank)?
- mitosis
- Cleavage
- very 1st mitotic divisions
- Stem cells
- totipotent cells; cells that can develop into any type of cell
- Blastomere -->
- morula (16 cels)
- Morula went through how many mitotic division?
- 2^4 4 divisions
- Morula-->
- blastocyst
- Blastocyst
- hollow sphere of cells
- Stage of stem cells & controversy
- blastocyst stage
- Implantation
- blastocyst travels into uterus & is implanted
- Human chorionic gonadotroph (HCG)
- secreted by the embryo to prevent menstration detected by pregnancy tests mother does not produce hCG
- Gastrula
- end of week 2 3 layered structure composed of tissues
- Ectoderm
- end of week 2 outside skin & nervous tissue
- Mesoderm
- end of week 2 middle muscle, connective tissue reproductive organs
- Endoderm
- Inside lining of organs, liver, pancreas
- End of week 2
- gastrula ectoderm mesoderm endoderm
- Chorionic Villi
- fingerlike structure that connect embryo to mom week 3 of development
- Week 10 of development
- fully developed fetus demands too much energy mom "kicks baby out"
- Placenta
- secretes hormones & moves nutrients to fetus
- Dizygotic twins
- fraternal 2 sperm fertilize 2 eggs 50% of same genes ex) mel & maron
- 2 sperm fertilize 2 eggs
- dizygotic
- Monozygotic
- identical 1 sperm fertilizes 1 egg egg splits in half at stage 2 clones genetically identical
- Birth defects
- often cause by something in environment
- Teratogens
- chemicals or other agents that cause birth defects
- Critical period
- time when a teratogen has an effect
- Thalidomide
- drug prescribed for morning sickness in the 50s & 60s disrupted limb development taught us womb is vulnerable
- Fetal alcohol syndrome
- leading known cause of mental retardation & birth defects
- Mendelian Genetics
- determined by a single gene
- Conclusions after mendels experiments?
- 2 genes for each character (1 maternal, 1 paternal) 2 different alleles (1 dominant, 1 recessive
- Law of segregation
- determines the type of gametes made alleles for a character segregate into different GAMETES for each chromosome you only get one copy on the gamete
- Autosomal dominant
- only need 1 copy to express itself found on non-sex chromosomes humans have 22 pairs of autosomes
- Autosomal dominant examples
- Huntingtons disease lactose intolerance polydactyly
- Autosomal recessive
- must have 2 copies of allele to express the trait
- Examples of autosomal recessive
- cystic fibrosis sickle cell disease pheylketonuria
- Dihybrid cross
- genetic cross in which 2 traits are tracked
- How many chromosomes are there in a human cell?
- 46
- X linked genes are found on...
- x chromosomes
- Heterogametic
- males XY make 2 different types of gametes
- Homogametic
- XX
- One gene affects the expression of another gene
- Epistasis
- Epistasis
- one gene affects the expression of another gene
- Which chromosome has a lot of genes?
- X
- SRY gene
- testes specific transcription factor codes for the transcription factor
- transcription factor
- protein that turns on other genes
- If SRY gene is missing or nonfunctional
- female development occurs XXY males XY females
- Males are (blank) for x linked genes
- hemizygous
- X-liked recessive
- expressed in females only when homozygous mothers give to sons & daughters fathers give to daughters only females have to get both from mom & dad to express it
- X-liked recessive examples
- hemophilia red/green colorbindness
- Hemophilia A
- recessive X-linked blood clotting disorder Affected people lack a clotting protein (factor VIII) More common in males
- Red-green colorblindness
- most common type recessive x linked more common in males
- X linked dominant
- rare can be lethal in males females only need one copy to express it
- X-inactivation
- occurs in female mammals one X chromosome condenses & becomes inactive
- Barr body
- part of x inactivation