Final Flashcards
Name three of Mendel’s laws
- Law of segregation,
- law of independent assortment,
- law of dominance
each gamete contains on allele of the two alleles possessed by the organism
Law of segregation
when examining multiple character, the traits for each character will assort independently of each other
law of independent assortment
when examining tow different alleles, the phenotype of the dominant allele will be displayed in the organism while the phenotype of the recessive organism will not be seen
law of dominance
what is the law of segregation
each gamete contains one allele of the two alleles posed by an organism
What is the law of independent assortment
When examining multiple characters, the traits for each character will assort independently of each other.
What is the law of dominance
When examining two different alleles, the phenotype of the dominant allele will be displayed in the organism while the phenotype of the recessive organism will not be seen.
Phenotypically, homozygous dominant and heterozygous organisms appear the same
the cross test
to differentiate between those two possibilities.
the purpose of the cross test
The dominant phenotype organism is crossed with a recessive phenotype organism
the purpose of the cross test
- If all of the offspring have the dominant phenotype, the unknown parental organism was homozygous for the dominant allele
- If the offspring are have a 1:1 ratio of dominant to recessive phenotypes, then the unknown parental organism was heterozygous for the dominant allele
Briefly describe the purpose of a test cross.
Phenotypically, homozygous dominant and heterozygous organisms appear the same. The purpose of the test cross is to differentiate between those two possibilities.
The dominant phenotype organism is crossed with a recessive phenotype organism
If all of the offspring have the dominant phenotype, the unknown parental organism was homozygous for the dominant allele
If the offspring are have a 1:1 ratio of dominant to recessive phenotypes, then the unknown parental organism was heterozygous for the dominant allele
There are three alleles for ABO blood type
- IA is responsible for making carbohydrate A
- IB is responsible for making carbohydrate B
- i does not make any carbohydrate
is responsible for making carbohydrate A
IA
is responsible for making carbohydrate B
IB
does not make any carbohydrate
i
ABO blood type is depended on the assortment of these three alleles.
The blood type is based on which carbohydrate(s) a person can make.
People with AB blood type make both carbohydrates (Genotype: IA, IB)
People with A blood type only make A carbohydrate (Genotype IA, IA or IA, i)
People with B blood type only make A carbohydrate (Genotype IB, IB or IB, i)
People with O blood type only make no carbohydrates (Genotype i, i)
People with AB blood type make both carbohydrates
Genotype IA, IB
People with A blood type only make A carbohydrate
Genotype IA, IA or IA, i
People with B blood type only make A carbohydrate
Genotype IB, IB or IB, i
People with O blood type only make no carbohydrates
Genotype i, i
The Rh blood system is governed by a pair of genes that assort independently of the ABO gene.
- Rh + individuals are either homozygous for the allele that makes the Rh protein or are heterozygous.
- Rh – individuals are homozygous for the allele that does not make the Rh protein
3) Briefly describe how the blood type is determined in the ABO and Rh blood system.
There are three alleles for ABO blood type
IA is responsible for making carbohydrate A
IB is responsible for making carbohydrate B
i does not make any carbohydrate
ABO blood type is depended on the assortment of these three alleles. The blood type is based on which carbohydrate(s) a person can make.
People with AB blood type make both carbohydrates (Genotype: IA, IB)
People with A blood type only make A carbohydrate (Genotype IA, IA or IA, i)
People with B blood type only make A carbohydrate (Genotype IB, IB or IB, i)
People with O blood type only make no carbohydrates (Genotype i, i)
The Rh blood system is governed by a pair of genes that assort independently of the ABO gene.
Rh + individuals are either homozygous for the allele that makes the Rh protein or are heterozygous.
Rh – individuals are homozygous for the allele that does not make the Rh protein.
4) Briefly describe the basis of sex determination in humans.
In humans and other mammals, there are two sex chromosomes, the X and Y chromosomes.
Females have two X chromosomes (XX)
Males have one X and one Y chromosome (XY)
Use a Punnett square to determine the ratios of phenotypes and genotypes of the F1 and F2 generations of the following crosses.
• Cross 1:
o Characteristic: Seed color
o Traits:
• Seed color: Yellow (Dominant, Y) and Green (Recessive, y)
o Parental (P) generation: YY crossed with yy
Possible gametes produced by parents: Parent 1: Y, Parent 2: y
F1 cross:
Y
y Yy
F1 genotype: Yy (100%) F1 phenotype: Yellow (100%)
F2 cross:
Possible gametes produced by parents: Parent 1: Y or y, Parent 2: Y or y
Y y Y YY Yy y Yy yy
F2 genotype: YY : Yy : yy, 1:2:1
F2 phenotype: Yellow : Green, 3:1
In the Punnett square what are thePossible gametes produced by parents: Parent 1: Y, Parent 2: y if the • Cross 1:
o Characteristic: Seed color
o Traits:
• Seed color: Yellow (Dominant, Y) and Green (Recessive, y)
o Parental (P) generation: YY crossed with yy
F1 cross:
Y
y Yy
F1 genotype: Yy (100%) F1 phenotype: Yellow (100%)
F2 cross:
Possible gametes produced by parents: Parent 1: Y or y, Parent 2: Y or y if the • Cross 1:
o Characteristic: Seed color
o Traits:
• Seed color: Yellow (Dominant, Y) and Green (Recessive, y)
o Parental (P) generation: YY crossed with yy
Y y
Y YY Yy
y Yy yy
F2 genotype: YY : Yy : yy, 1:2:1
F2 phenotype: Yellow : Green, 3:1
• Cross 2:
o Characteristic: Seed color and seed shape
o Traits:
• Seed color: Yellow (Dominant, Y) and Green (Recessive, y)
• Seed shape: Round (Dominant, R) and Wrinkled (Recessive, r)
o Parental (P) generation: YYrr crossed with yyRR
Possible gametes produced by parents: Parent 1: Yr, Parent 2: yR
F1 cross:
Yr
yR YyRr
F1 genotype: YyRr (100%) F1 phenotype: Yellow, Round (100%)
F2 cross:
Possible gametes produced by parents: Parent 1: YR, Yr, yR, or yr, Parent 2: YR, Yr, yR, or yr
YR Yr yR yr YR YYRR YYRr YyRR YyRr Yr YYRr YYrr YyRr Yyrr yR YyRR YyRr yyRR yyRr yr YyRr Yyrr yyRr yyrr
F2 genotype: YYRR (1) : YYRr (2) : YYrr (1) : YyRR (2) : YyRr (4) : Yyrr (2) : yyRR (1) : yyRr (2) : yyrr (1)
F2 phenotype: Yellow, Round (9) : Green , Round (3) : Yellow, Wrinkled (3) : Green, Wrinkled (1)
5) List the four stages that could have lead from atoms to the very simple cells
- The abiotic (nonliving) synthesis of small organic molecules, such as amino acids and nucleotides
- The joining of these small molecules into macromolecules, including proteins and nucleic acids
- The packaging of the molecules into “protobionts”, droplets with membranes that maintained an internal chemistry different from that of their surroundings
- The origin of self-replicating molecules that eventually made inheritance possible
of small organic molecules, such as amino acids and nucleotides
The abiotic (nonliving) synthesis
The abiotic (nonliving) synthesis
of small organic molecules, such as amino acids and nucleotides
The joining
of these small molecules into macromolecules, including proteins and nucleic acids
of these small molecules into macromolecules, including proteins and nucleic acids
The joining
The packaging of the molecules into “protobionts
droplets with membranes that maintained an internal chemistry different from that of their surroundings
droplets with membranes that maintained an internal chemistry different from that of their surroundings
The packaging of the molecules into “protobionts
molecules that eventually made inheritance possible
The origin of self-replicating
The origin of self-replicating
molecules that eventually made inheritance possible
6) Briefly describe the differences between the evolutionary theories of J.B. Lamarck and Charles Darwin
Both theories stated that organisms could change over time. Lamarck’s theory was that the offspring of an organism could inherit characteristics acquired over the parent organism’s life.
Darwin’s theory focused on natural selection on inherited traits changing the percentage of particular traits being passed on to the next generation.
Briefly describe the role of mutation
Mutations, changes in the DNA sequence of an organism, are the source of new alleles in a population. Mutations can be caused by errors in DNA replication or through the influence of external factors
Briefly describe the role of selection
Selection determines which alleles are passed on to the next generation. Traits that give an organism an advantage will be inherited by a larger percentage of the next generation
Briefly describe the role of gene flow in evolution
Gene flow is the movment of alleles into and out of a population by movement of fertile individuals. This can cause a change in the percentage of particular alleles in a population without selection.
Mutations, changes in the DNA sequence of an organism, are the source of new alleles in a population.
Mutations can be caused by errors in DNA replication or through the influence of external factors.
Selection determines which alleles are passed on to the next generation
Traits that give an organism an advantage will be inherited by a larger percentage of the next generation
determines which alleles are passed on to the next generation
Selection
changes in the DNA sequence of an organism, are the source of new alleles in a population
Mutations
can be caused by errors in DNA replication or through the influence of external factors.
mutations
Traits that give an organism an advantage will be inherited by a larger percentage of the next generation
selection
Gene flow is the movment of alleles into and out of a population by movement of fertile individuals
This can cause a change in the percentage of particular alleles in a population without selection.
is the movment of alleles into and out of a population by movement of fertile individuals
gene flow
This can cause a change in the percentage of particular alleles in a population without selection.
gene flow
8) Define the following terms: Homologous, vestigial
• Homologous structures are structures in different organisms that are inherited from a common ancestor.
o These structures do not necessarily have to have the same function
• Vestigial structures are structures that are no longer selected for.
o Vestigial structures may shrink or be lost over generations.
Homologous
Homologous structures are structures in different organisms that are inherited from a common ancestor.
o These structures do not necessarily have to have the same function
vestigial
Vestigial structures are structures that are no longer selected for.
o Vestigial structures may shrink or be lost over generations.
are structures in different organisms that are inherited from a common ancestor.
Homologous
These structures do not necessarily have to have the same function
Homologous
are structures that are no longer selected for
Vestigial structures
may shrink or be lost over generations
Vestigial structures