Week 5 & 6 Flashcards
Why is meiosis relevant to evolution?
Variation
What is a homologous chromosome?
It is one of a matching pair of chromosomes, each inherited from one parent. They are the same length and and have specific nucleotide segments called genes in exactly the same location.
It is a code for the exact same genes.
Define Genes and Alleles
Genes are a specific trait, located in the same area for each homologous pair. They are the functional units of chromosomes, they determine specifics physical characteristics by coding for specific proteins. They are part of our DNA sequence with info to build a protein.
Alleles are the different variants or forms for that trait (traits are variations of those characteristics). Alleles are genes variation that arise by mutation and exist at the same relative locations on homologous chromosomes . This then determines the traits. They are a copy of a gene.
Define Heredity and Inheritance
(Heredity) It tells us how traits are passed on from one generation to the next. It has an effect on transmitting genetic information from parents to offspring. (Eye color, haire color, heigh, intelligent, etc)
(Inheretance) Passing genetic information from the parents to the offspring (related to genetic descises)
Inheritance different types of variation
- Continuous variation: Characteristics that are determined by continuous or range scale
IE. Frequency of students(y)/Height(x) - Discontinuous variation: Characteristics that are determined by distinct categories
IE. Number of people(y)/Blood group(x)
Define Locus
It is the location of a gene on a chromosome.
Define Genotype and Phenotype
Genotype underlines genetic makeup (DNA coding). It contains physically visible and non-expressed alleles (it contains the sequence to make alleles)
(IE. Genes coded by enzymes)
Phenotype expresses and interact with two alleles for a given gene which produces physical observable traits (proteins) (IE. Person’s hight, blood type, enzymes, etc)
What is homozygous and heterozygous?
Homozygous is two of the same allele (ww & WW)
Heterozygous is two different alleles
Ww
What is recessive and dominant?
Dominant (is they are different) are the trait (allele) that is expressed despite the other allele. (Ww)
Recessive (if they are the same) is the trait (allele) that is only expressed if the other allele is the same. (ww or WW)
Define autosomal & sex-linked
Autosomal is when the gene is located on the non-sex, chromosome.
Sex-linked is a trait when a gene is located on a sex chromosome.
Describe Mendel’s experiment (monohybrid/dihybrid crosses)
The experiment was to prove that the parents pass on separate genes to their offspring that are responsible for inherited characteristics (with peas).
Monohybrid crosses have only one characteristic studied (IE. Flower color)
Dihybrid crosses have two characteristics studied simultaneously (IE. Pod color and Plant size)
What is codominance? Incomplete dominance? Complete?
Codominance is when two parents phenotypes are expressed together in the offspring.
Incomplete dominance is when the phenotype of the two parents blend together to create a new phenotype for their offspring.
Complete dominance is a form of dominance in the heterozygous condition wherein the allele that is regarded as dominant completely masks the effect of the recessive allele.
Explain laws of segregation & independent assortment
Laws of Segregation is that the parental genes must separate randomly and equally into gametes during meiosis so there is an equal chance of the offspring inheriting either allele (an organism’s reproductive cell - egg/sperm) (it is done randomly like in meiosis).
Independent Assortment describes how different genes independently separate from one another when reproductive cells develop (during meiosis the pairs of homologous chromosomes are divided in half to form haploid cells and this separation of homologous chromosomes are random).
Relate phenotype to protein activity
Phenotype is a multifactorial trait that often results from the contribution of many proteins.
What is a pedigree
It is a table or a list showing the line of ancestors of a person or animal.
