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88 Cards in this Set
- Front
- Back
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The study of hereditary is called ___________.
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genetics
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A gene is located inside _______ and serves as a recipe for _______.
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DNA
proteins |
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What two genotypes will produce the same results?
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homozygous dominant
heterozygous |
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A _______ is a physical characteristic.
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trait
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When pollen _______ an egg cell, a seed for a new plant is formed.
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fertilizes
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Pea plants normally reproduce by ___________.
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self-pollination
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What does it mean when pea plants are described as being true-breeding?
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that if they were to self pollinate, they would produce identical offspring to themselves
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To perform his experiments, how did Mendel prevent pea plants from self-pollination and control cross-pollination?
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he cut off the male parts and dusted pollen from another plant onto the plant
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What is the advantage to sexual reproduction?
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The wider the gene pool, the better for the species.
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What are chemical factors that determine traits?
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genes
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________ is the offspring of crosses between parents with different traits.
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hybirds
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Specific characteristics that vary from one individual to another are _______.
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traits
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A different form of the same gene is an __________.
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allele
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State the principal of dominance.
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some alleles are dominant, others recessive
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TRUE OR FALSE: An organism with a recessive allele for a particular form of a trait will always exhibit that form.
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false
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What traits were controlled by dominant alleles in Mendel's pea plants?
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tall, yellow
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Assume dominance is __________.
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complete
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What do the following symbols mean: P1, F1, F2
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P1-parent
F1-offspring F2- grandkids |
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How did Mendel find out whether the recessive alleles were still present in the F1 plants?
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he allowed all the F1 plants to produce an F2 generation by self pollination
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About one fourth of F2 plants from Mendel's F1 crosses showed the trait controlled by the ________ allele.
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recessive
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Mendel assumed that a ______________ had masked the corresponding recessive allele in the F1 generation.
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dominant allele
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At some point, the allele for shortness was _____________, or separated from the allele for tallness.
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segregated
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What are gametes?
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sex cells: sperm and egg
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During segregation, what are separated?
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chromosomes
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Dominant alleles are represented by:____________. Recessive alleles are represented by _________.
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capital letters
lowercase letters |
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The likelihood that a particular event will occur is called ___________.
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probability
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What is the probability that a single coin flip will come up heads?
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50 percent
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TRUE OR FALSE: The past outcomes of coin flips greatly affect the outcomes of future coin flips.
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false
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What can the principles of probability be used to predict the outcomes of genetic crosses?
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Because the way in which alleles separate is completely random.
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How do genetics use Punnett squares?
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to predict and compare the genetic variations that will result from a cross.
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What are the three types of genotypes?
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homozygous dominant
homozygous recessive heterozygous |
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Genetic makeup of an organism (Tt) is called _____________.
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genotype
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Organisms that have two identical alleles for a particular trait (TT or Tt) is __________.
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homozygous
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Physical characteristic of an organism (tall) is _____________.
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phenotype
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Organisms that have two different alleles for the same trait (Tt) is ____________.
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heterozygous
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Homozygous organisms are __________ for a particular trait.
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true breeding
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Do plants with the same phenotype always have the same genotype?
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no
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In Mendel's model of segregation, what was the ratio of tall plants to short plants in the F2 generation?
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3:1
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Can probabilities predict precise outcomes of an individual event?
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no
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How can you be sure of getting the expected 50:50 ratio from flipping a coin?
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repeat the experiment many times
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The ________ the number of offspring from a genetic cross, the close the resulting numbers will get to expected values.
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larger
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The ratios of an F1 generation are more likely to match Mendelian predicted ratios if ______________________.
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the F1 generation contains hundreds or thousands of individuals.
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In a two factor cross, Mendel followed ________ different genes as they passed from one generation to the next.
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two
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What combination best describes the F1 offspring of Mendel's two-factor cross:
1. homozygous dominant with round, yellow peas 2. homozygous recessive with wrinkled green peas 3. heterozygous dominant with round yellow peas 4. heterozygous recessive with wrinkled green peas |
heterozygous dominant with round yellow peas
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The genotypes of the F1 offspring indicated to Mendel that genes ______________.
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assort independently
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How did Mendel produce the F2 offspring?
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by crossing plants that were heterozygous dominant and then the alleles separated independently.
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What did Mendel observe in the F2 generation that showed him that the alleles for seed shape segregated independently of those for seed color?
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all possible phenotypes because the traits were not inherited together
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What were the phenotypes of the F2 generation that Mendel observed?
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round and yellow
wrinkled and green round and green wrinkled and yellow |
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What was the ratio of Mendel's F2 generation for the two factor cross?
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9:3:3:1
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State Mendel's principle of independent assortment.
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genes for different traits can segregate independently during the formation of gametes.
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When two or more forms of the gene for a single trait exist, some forms of the gene may be _______ and others may be _________.
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dominant
recessive |
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Do all genes show simple patterns for dominant and recessive alleles?
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no
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One allele is not completely dominant over another. The heterozygous phenotype is somewhere in between the two homozygous phenotypes: ________________.
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incomplete dominance
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In __________, both alleles contribute to the phenotype of the organism.
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codominance
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Genes have more than two alleles in __________.
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multiple alleles
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___________ mean that there are two or more genes controlling a trait.
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polygenic traits
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List Morgan's three criteria for a model organism for genetic studies.
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1. small
2. easy to keep in lab 3. able to produce large number of offspring in small amount of time |
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Mendel's principles of genetics apply not only to pea plants, but also to ____________.
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other organisms
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Characteristics are determined by interaction between genes and the ___________.
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environment
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In order for Mendel's principle of genetics to be true, two things are required:
1. 2. |
1. each offspring must inherit a single copy of every gene
2. when it produces its own gametes, the two sets of genes must be separated so each gamete contains one set of genes. |
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What does it mean to be homologous?
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That the organisms carry same genes, but that they are not identical. Each of the 4 chromosomes from the male parents has corresponding chromosomes from the female.
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What symbol describes a diploid cell? In this equation, what number would replace the variable to represent humans?
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2N
N= 23 |
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What symbol would represent a haploid cell?
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N
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A gamete is a ________cell.
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haploid
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A diploid contains _______ sets of homologous chromosomes.
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two
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How many chromosomes are in a haploid Drosophila cell?
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4
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How many times does cell division occur in meiosis?
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twice
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Meiosis separates DNA _______, but replicates ________. It starts with __% but finishes with _%, making it a haploid cell.
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twice
once 100 50 |
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What are the two divisions of meiosis?
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meiosis I
meiosis II |
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The diploid cell that enters meiosis becomes ____ haploid cells by the end of meiosis.
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4
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How does a tetrad form in prophase I of meiosis?
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each chromosome pairs with its corresponding homologous chromosome
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How many chromatids are in a tetrad?
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4
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What results from the process of crossing-over during prophase I?
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the exchange of alleles between homologous chromosomes and produces new combinations of alleles
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What are the three requirements of crossing over?
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1. whole gene must cross over
2. exact same gene must be transfered 3. must be homologous |
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During meiosis I, homologous chromosomes __________.
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separate
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Haploid gametes in females
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eggs
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haploid gametes in males
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sperms
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cells produced in females that do not participate in reproduction
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polar bodies
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Mitosis and meiosis begin with a____ cell. Mitosis produces _________. Meiosis produces________.
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diploid
two identical haploid cells four different haploid cells |
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What separates during independent assortment?
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chromosomes
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_______ groups are groups that tend to travel together.
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linkage
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What were Morgan's two conclusions about genes and chromosomes?
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1. each chromosome is actually a group of linked genes
2. genes don't separate, but chromosomes do, so Mendel's independent assortment is still true |
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Why didn't Mendel observe gene linkage?
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six of the seven genes he studied were on different chromosomes and two genes found on the same chromosome were so far apart that they assorted independently.
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Because of cross-over, some genes ___________.
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seperate
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Explain why two genes found on the same chromosome are not always linked forever.
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because of crossing-over, those closer together tend to stay together and those farther apart, tend to stay together
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The new combinations of alleles produced by crossover events help to generate genetic ___________.
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diversity
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What is a gene map? How is it constructed?
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it shows the relative locations of each known gene on a chromosome
the recombination rates of crossing over between genes |
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The higher the recombination frequency, the ____________, the lower the ____________.
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further apart
closer together |
