Unit 3 Genetics Flashcards
Genetic and genomic research can have social and environmental implications. Variability and diversity of living organisms from the distribution of genetic materials during the process of meiosis. All living things can be classified according to their anatomical and physiological characteristics. Human activities affect the diversity of living things in ecosystems.
Which bases used for DNA paired up together?
a) Adenine, cytosine/ thymine, guanine
b) Cytosine, guanine/ adenine, thymine
c) Adenine cytosine, guanine/ thymine
d) Guanine, thymine, adenine/ cytosine
b) Cytosine, guanine/ adenine, thymine
What would the probability be of getting a homozygous offspring in generation F2 with a p generation of a cross between a homozygous dominant and a homozygous recessive parent.
a) 50%
b) 100%
c) 0%
d) 25%
c) 0%
Why did Gregor Mendel use peas for his experiments?
a) Slow life cycle and production of many seeds
b) Rapid life cycle and the production of many seeds
c) Rapid life cycle and low production of seeds
b) Rapid life cycle and the production of many seeds
In a dihybrid cross between two heterozygous individuals, what is the expected phenotype ratio in the offspring?
a) 9, 3, 3, 1
b) 3, 1
c) 1, 2, 1
d) 12, 4
Answer is A
What is a somatic cell?
a) a body cell
b) a sperm cell
c) a gamete cell
d) a haploid cell
A somatic cell is simply a normal body cell, which is diploid. Sperm cells, or gamete cells, are sex cells specific for reproduction and are haploid.
A woman with type A blood has a type O child, what blood type could be the blood type of the father?
a) AB
b) O
c) B
d) All of the above
Crossing over occurs at which stage in meiosis?
a) Metaphase 1
b) Prophase 1
c) Prophase 2
d) Telophase 2
Crossing over only occurs in prophase 1 of meiosis. Synapsis brings homologous chromosomes together, forming a tetrad, that then exchange segments of DNA.
In cheetahs, the gene for fur pattern has two alleles. The dominant allele (L) codes large spots, while the recessive allele (l) codes for smaller spots. If the second generation consists of 50% heterozygous offsprings, and all offsprings have a dominant allele, what are the possible genotypes and phenotypes for both parents. Show your work with a punnet square.
- Since 50% of offsprings are heterozygous (Ll) and all contain dominant alleles, that means 50% are homogenous dominant (LL)
- In order to have 50% LL and 50% Ll genotypes, the parents have to have homogenous dominant (LL) and heterozygous (Ll) genotypes.
- Both parents have phenotype of 100% large spots
Which event occurs during meiosis that does not occur during mitosis?
a) Alignment of chromosomes during metaphase
b) Separation of sister chromatids
c) Synapsis of homologous chromosomes
d) Condensation of chromatin into chromosomes
Answer is C
Why don’t you look genetically identical to your parents and/or siblings? Explain using specific terms.
- During prophase 1 of meiosis, homologous pairs of chromosomes, forming tetrads, cross over for genetic variation
- These chromosomes that code for a certain trait are now genetically unique
After meiosis, each haploid daughter cell is genetically diverse - Our parents and siblings each had different gene codes in the gamete cells produced after meiosis, which is why, while we have the same genes, we do not look identical.
Which of the following describes the term “codominance”?
A) One allele completely masks the effect of the other allele
B) Both alleles contribute equally to the phenotype
C) Both alleles are recessive
D) The phenotype is a blend of two alleles
Answer:
B) Both alleles contribute equally to the phenotype
What is the term for different versions of a gene that can exist for a particular trait?
A) Genotype
B) Alleles
C) Chromosomes
D) Loci
Answer:
B) Alleles
In meiosis when do homologous chromosomes separate?
A) Metaphase I
B) Prophase I
C) Anaphase II
D) Anaphase I
Correct Answer: D
Which of the following is the best description of a Punnett square?
A) A diagram used to show the physical traits of an organism
B) A tool for predicting the probability of genetic outcomes in offspring
C) A model that demonstrates how genes are inherited through the environment
D) A method to determine the number of chromosomes in an organism
Answer:
B) A tool for predicting the probability of genetic outcomes in offspring
What is the difference between a genotype and a phenotype?
The difference between a genotype and a phenotype is that a genotype is the genetic makeup of an organism while a phenotype is physical characteristic of an organism
What is incomplete dominance and how does it differ from codominance?
incomplete dominance is when neither of the alleles is completely dominant over the other in turn the phenotype blends both traits. Codominance is when both alleles are fully expressed in the phenotype.
What is a homologous chromosome?
A) Chromosomes that are found in females
B) Chromosomes that come from different parents but carry genes for the same traits
C) Chromosomes that are found only in males
D) Chromosomes that do not carry similar genes
Correct Answer: b
What is true breeding?
True breeding is when an organism produces offspring that are genetically the exact same for one or more traits when self pollinated or when crossed with another true breeding organism for the same traits.
Which of the following is a method of asexual reproduction where a piece or fragment breaks off to form a brand new mature individual?
A) Budding
B) Cloning
C) Necrosis
D) Fragmentation
D - Fragmentation
Explanation: Like a starfish, when the arms grow off, they regenerate into a brand new starfish that grows full to a mature individual. Fragmentation is that process.
Which of the following is an example of a disadvantage of sexual reproduction?
A) Genetic diversity, provides the offspring with unique genetics
B) Allows for the combination of traits to be more flexible with environmental changes
C) Slower reproductive rate, making the process longer
D) Long-term survival of species within a population as the species reproduce
C - Slower reproductive rate, making the process longer
Explanation: The reproductive rate in sexual reproduction would be a slower process due to having to find a mate, then the mating process, and then the nurturing.
In a cross between a homozygous dominant (PP) pink tulip and a heterozygous recessive purple tulip (Pp), “P” is dominant and “p” is recessive, what is the colour ratio of the tulip?
A) 4:0
B) 3:1
C) 2:2
D) 1:3
A - 4:0
Explanation: As the pink tulip is the dominant trait, the homozygous dominant (PP) and the heterozygous recessive purple tulip (Pp), will turn out to be 100% pink and the dominant trait takes over the recessive trait.
What are the main differences between codominance, complete dominance, and incomplete dominance?
The differences between complete dominance, incomplete dominance, and codominance would be the phenotypes they produce in the final outcome. In complete dominance, only one allele is present in the offspring which is the dominant trait. In incomplete dominance, none of the alleles are fully present in the offspring, it is a blend between the two alleles. In codominance, both alleles contribute equally to the offspring’s appearance. The appearance would show both the alleles, like two different colours. They are all similar as they are the different ways alleles are shown in phenotypes, but they all have different ways of showing it.
What are the roles and benefits that DNA plays in living organisms? Are there any bad effects that DNA has on living organisms?
DNA has many roles and benefits that are good for living organisms. DNA provides living organisms with genetic information that is necessary for growth, development, and reproduction. The structure of DNA, the double helix shape, allows for it to hold the genetic information. The DNA’s ability to replicate ensures that genetic information is easily passed on to the next generation, keeping the population going. A bad effect that DNA can have on living organisms would be the passing of genetic diseases. Diseases like cancer could be passed down to the next generation, which could have a negative effect on that generation. DNA has good benefits and roles that lead living organisms to have good genes. Although the bad traits could be passed on, it doesn’t always tend to happen in all circumstances.
What is the difference between complete dominance and incomplete dominance? Show an example of both incomplete and complete dominance with alleles.
The difference between incomplete and complete dominance is that complete dominance is where one allele will completely take over and hide the recessive allele. On the other hand incomplete dominance is where neither of the alleles are dominant.
Example:
Complete dominance: Rr
Incomplete dominance: rr or RR