chapter 1 Flashcards
what is genetics?
branch of biology that deals with heredity and variation
what are genes?
segments of DNA that produce a functional product (RNA or polypeptide)
what is genetic variation?
root of natural diversity from differences in SNP
what are SNPs?
single nucelotide polyphormism- difference in one nucleotide
who was hippocrates and what did he discover?
-first to attempt an explanation of heredity.
-believed seeds were from various parts and transmitted to offspring.
-healthy seeds from healthy parts and diseased seeds from diseased parts
what did aristotle hypothesize?
-believed menstrual blood was the substance of reproduction, males provided heat that produced offspring
-offspring resembles parents due to spirits
what is preformation?
embryo developed because it contained parts of an adult in miniature form
what is epigenesis?
adult characteristics are not present at the beginning of conception but appear over the course of time.
what did william harvey do?
believed an organism develops from a fertilized egg by developmental events that turn into the egg of an adult
what did anton van leeuwenhoek do?
used microscope to observe sperm
what is homunculus?
fully formed human inside the egg/sperm that would enlarge to make a new individual
what did caspar friedrich wolff do?
cartried out studies of plant development and organ formation in chick embryos; argued that organs do not exists at the beginning of gestation
robert brown
showed that an opaque spot called the nucleus was present in a variety of plant cells
matthias schleiden
published research on plants indicating that they’re composed of cells
theodor schwann
published that animal tissue is made of cells
what did charles darwin do?
determined that species evolve by natural selection
what did gregor mendel do?
-father of genetics
-pea plant experiment that concluded that traits are controlled by a pair of factors and during gamete formation, they split
-work ignored until 1900s
how many chromosomes?
46 (diploid; 22 pairs + xx/xy)
what did walther flemming do?
described the movement of chromosomes during cell division=mitosis
what did walter sutton and theodor boveri do?
noted that the behaviour of chromosome in meiosis is identical to the behaviour of genes during gamete formation, described by mendel.
what is the chromosome theory of inheritance?
traits are controlled by genes on the chromosome that are transmitted through gametes, maintaining genetic continuity from generation to generation
what are alleles?
alternative forms of a gene
eg. normal white eye gene (1), mutant white eye gene (2)
what are genotypes?
set of alleles for a given trait (Ff or Bb)
what are phenotypes?
observable traits produced by the expression of the genotype
who discovered that DNA was the carrier of genetic information?
avery macleod and mcCarty
what was the mouse experiment?
live R bacteria took up DNA fragments from dead S bacteria and started expressing viral factors of the dead S bacteria- killing the mouse
-used DNase with s type extract and no transformation occured, concluding it was in the DNA
what did james watson and francic crick do?
described the structure of DNA using xra crystallography from rosalind franklin
what is each DNA strand made up of?
-a sugar (Deoxyribose) bonded to a phosphate + a nitrogenous base (A,T,C or G)
-A binds with T and C with G, with two strands running anti-parallel 5’-3’
what is the structure of RNA?
single stranded, ribose sugar and uracil instead of thymine
what is the central dogma and who discovered it?
states that gene expression occurrs by a series of steps that result in a functional gene product; DNA to RNA to protein; francis crick
how do you link genotype to phenotype?
mutations that alter genes may modify or eliminate a proteins usual function, causing an altered phenotype
what is an example of a mutation?
hemoglobin protein has a CTC codon, it gets mutated to CAC, created a different amino acid and changed the structure of the red blood cell causing it to stick to the capillaries= sickle cell anemia
what are the types of traits?
morphological- physical appearance (flower colour)
physiological- cellular or body function (digesting lactose)
behavioral- ways organisms respond to environment ( mating calls)
what are restriction enzymes?
can cut DNA at specific sites
what is the process of cloning DNA sequences?
DNA fragments od interest are cut using restriction enzymes and inserted into a carrier DNA molecule called vectors, RDNA is then transferred to bacteria which would make thousands of copies.
what are transgenic organisms?
genetically modified organisms to increase insect or viral resistance, nutritional enhancement or longer shelf life
how are transgenic animals used in medicine?
antithrombin, an anticlotting protein that was expressed in the milk of transgenic goats was approved in 2009
- human gene producing normal amounts of antithrombin protein is inserted into goat DNA, then inserted into the nucleus of a fertilized goat egg and extracting the protein from the goat milk.
how was dolly the sheep cloned?
nucleus from an adult sheep was placed in an embryo and grown
why didn’t dolly the sheep live long?
the sheep used to clone molly was 6 years old meaning the telomeres were shortened, once cloned, the baby sheep had the telomeres and the DNA of an adult sheep making her age faster than normal.
what are model organisms?
allows researchers to compare their results and determine scientific principles that apply to other species as well
why do scientists use model organisms?
theyre easy to grow, have a short life cycle, produce many offspring and genetic anlysis is straight forward
