What is the ultimate source of genetic variation?
mutations
What is a mutation?
any change in the nucleotide sequence of DNA
Why are mutations important?
1. basic requirement for evolution-source of new ales 2. drug/antibiotic/pesticide resistance 3. involvement in cancer, aging, etc
Mutations can change what in a protein?
amino acids
What are the types of mutations?
substitution, insertion/deletion, or frameshift
What are substitution mutations?
one base in the DNA is changed
What is an example of substitution mutation?
sickle cell anemia- caused by a single base substitution of GAA to GUA
What are the two general categories mutations within a gene can be divided into?
1. nucleotide substitutions(replacement of one base to another) 2. nucleotide deletions ot insertions ( loss or addition of a nucleotide)
What type of disorder is sickle cell anemia?
autosomal recessive disorder
True or False. All genes are expressed at the same time?
False.
In cellular differentiation, cells become specialized in
structure and function
Certain genes are turned off and on in the process known as
gene regulation
in gene expression
a gene in turned off and transcribed into RNA and info flows
Operon
includes a cluster of genes with related functions and control sequences that turn on and off genes
The lac operon uses?
a promoter, an operator, and a repressor
Transcription factors
proteins that bind to DNA sequences called enhancers
Silencers
repressor proteins that bind to DNA and inhibit the start of transcription
Activators
turn genes on by binding to DNA (more typically used by eukaryotes than silencers)
Alternative RNA splicing
exons may be spliced together in different combinations, producing more than one type of polypeptide from a single gene
How many eons do human genes typically contain?
10
What are the master control genes called?
homeotic genes
What of homeotic genes regulate?
regulate groups of other genes that determine what body parts will develop in which locations
Cancer cells
-experience changes in the gene expression and -escape from the control mechanisms that normally limit their growth and division
Characteristics of cancer cells?
1. lack differentiation 2. have abnormal nuclei 3. form tumors 4. undergo angiogenesis( formation of new blood vessels) and metastasis (establishing new tumors)
Oncogenes
are genes that cause cancer and are found in viruses
Proto-oncogenes
-are normal genes with the potential to become oncogenes -often genes that code for growth factors
Tumor-supressor genes
-inhibit cell division -prevent uncontrolled cel growth -may be mutated and contribute to cancer
In familial or inherited cancer
the mutation is passed from one generation to the next
carcinogens
cancer causing agents found in the environment including: -tobacco products -alcohol -exposure to ultraviolet light
DNA profiling
can be used to determine if two samples of genetic material are from a particular individual
polymerase chain reaction
is a technique to copy quickly and precisely a specific segment of DNA
Repetitive DNA
consist of nucleotides sequences that are present in multiple copies in the genome
Short tandem repeats (STRs)
short sequences of DNA and are repeated many times in the genome
STR analysis
is a method of DNA profiling that compares the lengths of STR sequences at specific sites in the genome
gel electrophoresis
a method for sorting macromolecules-usually proteins or nucleic acid-primarly by their electrical charge and size
What do the differences in locations of bands of DNA fragments reflect?
the different lengths
What can DNA profiling be used for?
-test the guilt of suspected criminals -identify tissue samples of victims -resolve paternity cases -identify contraband animal products -trace the evolutionary history of organisms
Gregor Mendel(1860's)
was the first person to analyze patterns of inheritance and deduced fundamental principles of genetics
Character
heritable feature, such as flower color
Trait
variant of a character, such as a white flower
gene
segment of a chromosome that is responsible for a genetic trait
locus
specific position of a particular gene on a chromosome
alleles
alternate forms (flavors) of the same gene on a pair of homologs
Dominant allele
always expressed in the individual
Recessive allele
expressed only id the dominant allele is not present
A person's genotype determines their
phenotype
homozygous chromosomes
pair of identical alleles
heterozygous chromosomes
pair of different alleles
Medel studied garden peas because they:
-were easy to grow -came in many readily distinguishable varieties -are easily manipulated -can self-ferilize
What is the P generation?
parental generation
What is the F1 generation?
1st generation offspring
What is the F2 generation?
2nd generation offspring
Medel's Theory of Segregation
Alleles for a gene separate during meiosis: each gamete receives only one allele for a gene
Medel's Theory of Independent Assortment
Different homologs assort independently form one another.
True or False? Homologous chromosomes are formed by DNA replication
False
How many times does the calvin cycle have to cycle(go around) to produce 1 molecule of glucose?
2
In expose a photosynthesizing plant to carbon dioxide that contains radioactive oxygen, which of the products of photosynthesis will be radioactive?
glucose
If the triplet codes in the DNA template strand were ATG-CGT. the tRNA anticodons would be:
AUG-CGU
Both cellular respiration an and photosynthesis rely on electron transport chains embedded in membranes to produce ATP molecules. Which of the following correctly describes the difference between the two types of electron transport chains?
In cellular respiration, the electron source is energy-rich food and the final electron destination is oxygen
In energy metabolism what are the energy sources?
lipids, polysaccharides, proteins.
Incomplete dominance
one allele is not fully dominant over it's partner (e.g.,flower color in snapdragons)
Polygenic inheritance
the additive effects f two or more genes on a single phenotype
Many human characters result from a combination of?
heredity and environment
Turners syndrome (girls)
short stature, loss of ovarian function, women are usually infertile, hormone imbalances, stress, and emotional deprivation, diseases affecting the kidneys, heart, lungs, and intestines, bone. only one x chromosome. 1 in 2500
Klinefelter's syndrome
instead of XY these males have XXY-consider themselves transgender, more feminine. 1 in 500 to 1000
Features of Klinefelter's syndrome
tall, sexually underdeveloped, infertility, sparse facial and body hair, developmental delays, increased risk of autoimmune disorders, breast cancer, osteoporosis, leg ulcers, depression, and dental problems
Darwin's Theory of Evolution by Natural Selection
1. Individuals in a population vary-no two are alike. 2. Much of this variation is heritable
Microevolution
change at the genetic level
Macroevolution
change at the species level
Population
a group of individuals of the same species, living in the same place and the same time
Gene pool
all of the alleles of all the genes in a population
The Hardy-Weinburg formula
p^2 + 2pq +q^2 =1
What is the Hardy-Weinburg formula used to calculate?
the percentage of a human population that carries the allele for a particular inherited disease
Mechanisms of evolutionary change
1. Mutation 2. Natural selection 3. Nonrandom mating 4. Gene flow 5. Genetic drift
Gene flow
a change in the gene pool due to immigration or emigration of individuals in and out of a population
Genetic drift
a change in the gene poll due to chance events in small populations or as the result of disasters
What are the two kinds of genetic drift?
bottleneck effect and founder effect
What is the bottleneck effect?
a severe reduction in population size
What is the founder effect?
a few individuals from an existing population establish a new one
Nonrandom mating
changes in gene pool due to selective mating