Chapter 4 Flashcards
all organisms inherit genetic information specifying their ____ and ____ from their parents
structure and function
all cells arise from preexisting cells, so the genetic material must be replicated and passed from parent to progency each ______
cell division
The classical principles of genetic were deduced by Gregor Mendel in 1865, from his experiment with _________
pea plants
Mendel studied well-defined traits, such as _____, and could predict _____ by assuming each trait is determined by a pair of inherited factors, now called ___________-
he studied pea plants
well defined traits such as seed color
he predicted patterns of inheritance
inheritable factors called genes
one copy _____ specifying each trait is inherited from each parent
allele
His progeny (f generation) were hybrids that had yellow seeds yellow ____ and green _____
yellow dominant
and green recessive
define genotype
is the genetic makeup of an individual
define phenotype
it is the resulting physical appearance. the genotype of the F1 generation is Yy the phenotype is yellow.
A dominant: recessive = (whats the ratio?)
3:1
most cells of plants and animals are ____: containing two copies of each chromosome
diploid
define meiosis
only one member of each chromosome pair is transmitted to the progency cell
the sperm and egg are _____: containing one copy of each chromosome
haploid
at fertilization, two ___ cells are combined to make a new _____ cell
haploid
diploid
The fundamentals of mutation, genetic linkage, and relationships between genes and chromosomes were largely established by experiments with the ________
fluid fly, drosophila melangoaster
in the early 1900s ___________________ were observed in the drosophila (fruit fly) that affected characters such as eye color and wing shape
mutations (genetic alterations)
breeding experiments showed that some of these genes are inherited independently of each other. This suggests that the genes are ______ chromosomes that segregate independently during meiosis
diffwerent chromosomes
genes located on the ___ chromosome are inherited together and are said to be linked
same chromosome
genes located on the ___ chromosome are inherited together and are said to be linked
same chromosome
DNA is a ______
double helix
the backbones of DNA is made out of ____ whiles the outside is made of ____ and the inside is hydrogen bonds formed between purines and pyrimidines on opposite chains. The base paring is very specific: A always Pairs with T and G with C
backbones= sugar, phosphate
outside=bases
the DNA helix turns every ___ nm. the distance between adjacent bases is ______nm
3.4 nm… distance between adjacent bases is 0.34 nm
semiconservative replication is?
one strand of parental DNA is conserved in each progeny DNA molecule
in the presence of DNA to act as a template ______ directed the incorporation of nucleotides into a complementary DNA molecule
DNA polymerase
although DNA appeared to specify the order of amino acids in proteins, it did not necessarily follow that DNA itself directs protein synthesis. DNA is located in the nucleus of eukaryotic cells, but protein synthesis occurs in the ___________
cytoplasm
RNA is single stranded, its sugar is _____ and it contains ___ instead of thymine (T), but this does not affect base- pairing
ribose, uracil
Whats the pathway for the flow of genetic information (aka central dogma)
DNA—> RNA—> Protein
RNA is synthesized from DNA templates (_______) , and proteins are synthesized from RNA templates (_______)
transcription, translation
RNA polymerase: synthesis of ______ from a DNA template
messenger RNA (mRNA)
Ribosomal RNA (rRNA)
is a component of ribosomes, sites of protein synthesis
Transfer RNAs (tRNAS)
align amino acids along the mRNA
some viruses contain RNA instead of DNA these viruses encode an _______:
catalyzes synthesis of RNA from and RNA (RNA-directed RNA synthesis) most animal viruses replicate in this way. One group ( RNA tumor viruses) require DNA synthesis in infected cells.
these viruses (now called _____) replicate via synthesis of DNA intermediate, a DNA provirus
enzyme
retrovirus`
Reverse transcriptase: experimentally to generate DNA copies of RNA molecule
define recombinant DNA technology:
isolate, sequence, and manipulate individual genes from cell
define restriction endonucleases:
they cleave DNA at specific sequence Bacteria have a variety of restriction endonucleases that cleave DNA at more than `00 distinct recognition site
How does EcoRI digestions and gel electrophoresis of lambda DNA
ECORI recognizes the sequence GAATTC five sites in DNA of the bacteriophage lamda, so ranging from 3.6 to 21.2 kilobases
the fragments of DNA can be separated by __________-
electrophoresis
define the components and how electrophoresis works?
- a gel of agarose or polyarcylamide is placed between two electrodes and the sample is added to the gel. nucleic acids are negatively charged so the migrate towards the positive electrode
- smaller molecules move through the gel more rapidly, allowing the fragments to be separated by size
_______ are commonly used for cloning DNA inserts of up to a few thousand base pairs
plasmids
plasmids have an ____________ - the DNA sequence that signals the host DNA polymerase to start replication.
Plasmid vectors also carry genes that confer resistance to antibiotics, so bacteria carrying the plasmids can be selected for
origin of replication (ori)
Gene function can be studied by introducing cloned DNA into plant and animal cells (___________)?
gene transfer
methods were initially developed using infectious viral DNA, thus it is called ______
transfection
what are some other methods in which you can get gene function in eukaryotes:
- direct microinjection into the nucleus
- coprecipitation of DNA with calcium phosphate to form small particles that are taken up by the cells
- incorporation of DNA into LIPOSOMES that fuse with the plasma membrane
- exposure of cells to brief electric pulses that open pores in the plasma membrane (ELECTROPORATION)
cloned genes can also be introduced into the germ lines of multi cellular organisms. Mice that carry foreign genes (________) are produced by micro injection of cloned DNA into the pro nucleus of fertilizer egg
transgenic mice
___________________________ are also used to get cloned genes into mice. cloned DNA is introduced into ES cells in culture, then transformed cells are introduced back into mouse embryos. the offspring are chimeric. a mixture of cells that arise from normal and transfected embryonic cells
embryonic stem (ES) cells
