Genetics Flashcards
what is DNA?
- a long molecule that contains a set of instructions for all cell processes
- stands for deoxyribose nucleic acid
what are the DNA bases? (4)
A-adenine
T-thymine
C-cytosine
G-guanine
what does the order of bases code?
-a message that the cell can read and certain proteins can be made
what are proteins?
-they are responsible for cell functions and characteristics that can be passed down from generation to generation
what is a gene?
-a section of DNA that contains the information to make a protein
what are chromosomes?
-long strands of tightly coiled DNA
how many chromosomes are in the human body?
- 46 total
- 2 sets of 23 chomosomes
what are pairs of chromosomes called and why?
- homologous chromosomes
- contain the same genes
how many genes per human chromosome?
-hundreds
what happens when a protein needs to be made?
-chromosome containing the gene needed unwinds to expose instructions
who is the father of genetics?
-Gregor Mendel;austrian monk
what did mendel study to determine the study of genetics?
-pea plants bc they have easily inheritable characteristics
heredity?
-passing on of traits/characteristics to offspring
genetics?
-the study of heredity
allele?
-the different versions of a gene
when is a dominant allele expressed?
-whenever present and masks or hides other alleles of the same gene
when is a recessive allele expressed?
-not expressed when dominant allele is present
how many copies do humans have from each gene?
- two copies
- one from either parent
homozygous?
- both alleles are the same
- also known as purebred or pure
heterozygous?
-when the alleles are different
genotype?
-the combination of alleles that an organism possesses
phenotype?
- the outward (physical) appearance of an organism
- does not necessarily tell which alleles an organism has for a particular trait
in the law of independent assortment…?
-no trait has anything to do with any other trait
what does the law of independent assortment work for?
-genes on different chromosomes
what does the environment play a role in?
-the expression of a genotype in a phenotype
what are the four types of inheritance?
- complete dominance
- codominance
- incomplete dominance
- sex-linked traits
what is complete dominance?
-when the dominant allele is completely dominant over the recessive allele
what is codominance?
- neither allele is dominant to each other
- both alleles are completely expressed in the hybrid
what happens when a trait has several different allele forms?
-a gene with more than two alleles is said to have multiple alleles
how many alleles does human blood have?
- 3
- allele A (equal dominance or codominance between A and B)
- allele B
- allele C (recessive to A and B)
what is incomplete dominance?
- where individuals that are heterozygous exhibit a mixture of the traits displayed by its purebred homozygous parents
- there is a blending of the traits from each of the parents to form a intermediate phenotype
what is the ration of incomplete dominance if the F1 generation crossed themselves?
-1:2:1
what is blood typing?
-a method of classifying blood based on the presence of absence of specific proteins on the surface of red blood cells
who discovered ABO blood typing?
- Karl Landsteiner, Austrian physician
- late 1800s