Section 2 Flashcards
What was the scientific objective of Mendel’s experiments?
To study how traits are transmitted over generations
In the nineteenth century, what was the dominant theory for how traits were inherited?
“blending inheritance”
What did Mendel study in Vienna?
Botany
What was the practical goal of Mendel’s experiments?
To learn if crossbreeding could produce a new, profitable form of crop for the monastery and landowners in face of competition from abroad
How many times did Mendel fail in getting his teaching certificate?
Twice
What organism did Mendel choose as the subject of his experiments?
Common garden pea
What is the scientific name of the common garden pea plant?
Pisum sativum
What turned out to be the key decision that helped Mendel revolutionize the field of genetics?
His decision to use the common garden pea plant
What traits of pea plants allowed Mendel to conduct large-scale self- or cross-pollination experiments?
1) traits that can be easily described and distinguished
2) easy to cultivate
3) reproduce quickly
4) pollination is easy to manipulate due to their relatively large sized flowers
What were the seven traits Mendel chose?
1) position of flower
2) color of flower
3) shape of pea pod
4) color of pea pod
5) shape of peas
6) color of peas
7) height of plant
What variety of plants did Mendel choose?
Several stocks of true-breeding varieties
How many traits were available for Mendel to pick from? How many did he pick?
34; he chose 7
What was significant about the traits Mendel chose?
They each had only two distinct variants
Mendel crossed and followed individual plants that differed in only ________ trait over several generations.
One
Between 1854 and 1865, how many plants did Mendel meticulously observe and document?
about 30,000
Every gene codes for the production of one or more ______.
proteins
Each ______ determines a particular trait, which is either expressed externally or is manifested internally as a complex network of metabolic reactions.
protein
All somatic cells in our body are ______.
diploid
What are chromosomes with the same complement of genes called?
homologous chromosomes
Homologous chromosomes have the same gene at a given ______.
locus
How do genes at a given loci compare?
they contain the same or a slightly different nucleotide sequence
The pairs of genes at a given loci are called?
alleles
If two alleles nucleotide sequences are virtually the same, they are called?
homozygous alleles
If alleles have different nucleotide sequences, they are called?
heterozygous alleles
In general, a ______ allele implies that the gene that codes for the particular trait is mutated in such a way that its protein product is defective.
recessive
Chromosomes 1 through 22 are _______ chromosomes.
autosomal
The 23rd pair of chromosomes are called the….
sex chromosomes
The paternal autosome #1 and the maternal autosome #1 are an example of what?
homologous chromosomes
In a test cross, if the hybridization experiment investigates only a single trait, it is called a…..
monohybrid cross
Which test cross investigates two traits simultaneously?
a dihybrid cross
Mendel was the first person to systematically apply ________ in predicting and analyzing results in the study of genetics.
mathematical principles
What were the two rules of probability Mendel used were?
The product (multiplication) rule and the sum (addition) rule
The third mathematical rule Mendel used was?
binomial theorem
What was the ratio Mendel consistently identified?
3:1
What act of Mendel marked the birth of modern population genetics?
he counted the number of plants with each phenotype
What did Mendel name his “heritable factor”?
an allele
Mendel’s observation that in his F1 generation, one allele was responsible for the dominant phenotype and another for the recessive phenotype, came to be known as?
Mendel’s law of dominance
“The pair of alleles in any combination has to be temporarily separated and then re-combined during fertilization.” This observation of Mendel came to be known as?
his law of segregation
The law of _______ states, “each pair of alleles for a particular characteristic at a given locus segregates independently of alleles at other loci.”
Mendel’s law of independent assortment
What was the name of the obscure local journal Mendel published his work in, where it received little attention? What year?
Experiments on Plant Hybridization in 1866
How many decades passed before Mendel’s work was rediscovered?
3 decades
What was Mendel’s first major contribution?
his rejection of the “blending inheritance” idea
What was Mendel’s second major contribution?
He realized that each gene that controls a certain trait comes in two forms, called alleles.
What was Mendel’s third major contribution?
his prediction that one allele may dominate over the other
What was Mendel’s fourth and most important major contribution?
By proposing the law of segregation, he laid the foundation for the understanding of how meiosis works.
It is the ______ that dictates the expression of a particular trait.
protein
The segregation of homologous chromosomes during gamete formation was not completely understood until shortly before _________, with the work of ___________.
WWI; Thomas Morgan
During gamete formation, the sperm/egg becomes ________.
haploid
In meiosis, each pair of homologous chromosomes is separated from each other during _________.
Anaphase I
A hybridization experiemtn in which two plants being crossed are hybrid for two independent traits is called a ______ cross.
dihybrid cross
Mendel’s fifth and final major contribution was?
his hypothesis that two distinct traits would be sorted into separate gametes independent of each other (law of independent assortment)
The chances that two genes that are not linked will be packaged together during meiosis and transmitted to the offspring is highly _______.
unlikely
Mendel focused on one to a maximum of ______ traits at anyone time.
3
Mendel was elected to the position of ______ (equivalent to a bishop) in the monastery in 1868 and became heavily burdened with _________.
prelate; administrative duties
Mendel indicated he was “convinced it [his work] will be appreciated before by the whole world,” prior to his death in ______.
1884
How many years after Mendel’s death did Hugo de Vries launch a plant-breeding program?
Six years
Now, almost _____ years later, the paper that was ignored by most of Mendel’s contemporaries is still considered one of a handful of seminal studies that have revolutionized biology.
150 yrs
Mendel’s results were repeated and confirmed by other scientists using different models and eventually led to the formation of _________.
the theory of genetics
Of the seven traits Mendel selected to study, non affected the ________ of the plants.
Survival
Earlobe attachment, widow’s peak, and hitch-hikers thumb in humans are example of what kind of traits?
single gene controlled traits
What year was the human genome project completed?
2003
Consensus among scientists working on ___________ has been that “All diseases have a genetic component, whether inherited or resulting from the body’s response to environmental stresses like viruses or toxins.”
The Human Genome Project
When did Archibald Edward Garrod describe the first disease linked to genes? What was the name of this disease?
1902; it was called alkaptonuria
What is the alternate name for alkaptonuria?
Black urine disease
Alkaptonuria is an autosomal ________ condition in which the gene responsible for the the enzyme involved in the metabolism of an amino acid is mutated, and thus the enzyme becomes defective.
recessive
To signify the genetic nature of the disease, Garrod called alkaptonuria an “________________.”
inborn error of metabolism
Cystic fibrosis is what kind of genetic disease?
homozygous recessive
This disease occurs when a gene that codes for a channel (transport) protein located on the surface of most cells is mutated and results in the accumulation of thick and sticky mucous in the breathing passages of the lungs and the lining of the digestive system.
Cystic fibrosis
Which disease is the most common genetic disease in the US?
Sickle cell anemia
Which genetic disease affects one in four hundred African Americans?
Sickle cell anemia
A single _______ substitution results in the wrong amino acid being added to hemoglobin and causes the protein to be folded incorrectly in sickle cell anemia.
nucleotide
