Heredity And Evolution Flashcards
What is heredity?
The process of passing traits or characters from parents to offspring.
The offspring of parents is also called ________.
progeny
Explain the 2 types of traits.
[A] Inherited traits
- They are the traits that are transferred from parents to offspring.
- eg; height, skin, color, hair, etc.
- These are present in genes.
- These are genetic variations caused in the DNA inside the nucleus
[B] Acquired traits
- Traits that are developed throughout the lifetime of the individual.
- eg; learning skills
- These are somatic variations which are caused outside the nucleus.
The opposite of genetic is ___________ .
Somatic
__________ is also called the father of inheritance.
Gregor Mendel
How Gregor Mendel found out the rules for inheritance?
He studied the lifespan of pea plant (also called Pisum Sativum) to find out the rules of inheritance. He choose pea plant because -
- It was easy to grow.
- It had short life cycle (around 3 months) and therefore, it was easy to study a large number of generations of that.
- Pea plants are bisexual too.
- It has 7 pairs of contrasting characters.
What is dominant trait?
The trait which expresses itself both in the presence and absence of the recessive trait.
What is recessive trait?
The trait which expresses itself only in the absence of dominant trait.
What is Allele?
Different forms of a given gene are called alleles.
eg, T-allele is responsible for tallness.
t-allele is responsible for dwarfness.
What is phenotype?
It refers to observable physical appearance of a given organism.
eg; tall plant, round seeds, etc.
What is genotype?
It refers to the genetic code responsible for any given phenotype.
eg; (TT) - is responsible for tallness
(tt) - is responsible for dwarfness
What is the difference between Homozygous and Heterozygous?
Homozygous refers to the condition when same type of allele is present for a given phenotype. eg; tt, TT.
Heterozygous refers to the condition when different type of allele is present for a given phenotype. eg; Tt
The study of single trait is called _________ .
Monohybrid Cross
The study of single trait is called _________ .
Monohybrid Cross
The children of parental generation is called _________, while the child of the children of parent generation is called _____________.
First filial generation (F1)
Second filial generation (F2)
The ratio of all possible genotypes is called ___________ .
genotypic code
The ratio of all possible phenotypes is called ____________.
Phenotypic ratio
The possibilities of offspring can be represented through ___________.
Punnett Square
Describe Mendel’s Principles.
- Law of Dominance - some alleles are dominant and cover up the recessive alleles.
- Law of Segregation - The allele that exist in pairs that separate during gamete formation. which means for a Tt organism, some of its gametes will have T allele and some will have t allele. So, depending upon which male gamete fertises which female gamete, the new zygote will possess that traits.
- Law of Independent Assortment - The alleles of different genes are inherited independently within the organisms which reproduce sexually.
which means that the 2 genes transferred are not in packets so one allele has nothing to do with the other
Describe Sex determination in Humans.
In human body, each cell has 46 chromosomes, these chromosomes are 23 in pair. In males, the one pair is a pair of X chromosome and Y chromosome. In females, the one pair is a pair of X chromosome and X chromosome. These X and Y chromosome are called sex chromosomes.
When male gamete fuses with the female gamete, then if the male gamete contained X chromosome which when fuses with the female’s X chromosome, then the result is a female, but if the male gamete contained Y chromosome, then the result is a male.
Chromosomes in humans other than sex chromosomes are called _____________ .
Autosomes
How traits get expressed?
Cellular DNA is the information source for making proteins. A section of DNA that provides information for one protein is called the gene for that protein.
According to the genotypes, the proteins will manufacture some particular enzymes which will make that particular hormone which will trigger to express a particular trait.
According to genotypes, more, less for medium efficient hormones will be made which will trigger to express a particular trait.
__________ produces enzymes in our body.
Amino acids
State true or false:
does every cell of the body has the same DNA?
True