genetics test Flashcards
what is mitosis?
cell division of somatic cells that ends up with two identical daughter cells. The purpose is for repair and growth.
what is meiosis?
cell division resulting in daughter cells with half the amount of chromosomes as the original amount.
what is an eukaryotic cell?
cell with genetic material in the nucleus
what is a chromatin
loosely arranged chromosomes during interphase
what is a chromosome?
thread shape dna and proteins that form when the chromatin changes during cell division.
what is a karyotype
representation of a complete set of homologous chromosomes in order.
what is dna composed of?
nucleotide
structure of a nucleotide
nitrogenous base, phosphate group and deoxyribose sugar.
what are the four nitrogenous bases?
thymine, adenine, cytosine, guanine
which nitrogenous bases are pyrimides and which are purines?
adenine and guanine are purines, and thymine and cytosine are pyrimides.
what is a character trait?
physical, psychological or phisiological attributes of an organism.
what is a gene
a particular sequence within dna that codes for proteins
what is a protein
molecule composed of amino acids
what is a genome
complete set of genes within an individual
what is dna replication
dna duplicates during interphase so that there is the right amount of identical chromosomes
what are the enzymes involved in dna replication
DNA helicase, DNA polymerase, DNA ligase
what are the roles of proteins
support, transport, message and control, catalysis
what is protein synthesis
the manufacturing of proteins from the instructions found in DNA
what is RNA
single stranded messenger that carries instructions from DNA to the ribosome where proteins are manufactured
what are the ribonucleic bases found in RNA
cytosine, guanine, uracil, adenine
what is mRNA
messenger RNA that carries copied instructions from DNA out of the nucleus to the ribosome
what is tRNA
transfer RNA that carries amino acids from the cytoplasm to the ribosome
what is dna transcription
DNA unzips and is copied by mRNA so it can be taken out of the nucleus
what is mRNA attachment
After copying the dna code, the mRNA leaves the nucleus and attaches to the ribosome in triplets.
when does protein start to be maufactured?
when there is a start codon (triplet)
what is translation into a protein
ribosome reads the mRNA in triplets (which are all associated with a specific amino acid), and the tRNA bring complementary code to the codons (anticodons)
how does protein synthesis finish?
the ribosome reaches a stop codon that completed the amino acid strand. The strand diconnects from the tRNA to form a completed synthesized protein.
what is an amino acid
the building blocks of proteins
how many different amino acids are there
20
what are essential amino acids
amino acids that cannot be synthesized by organisms. (have to be ingested)
what is heredity?
transmission of parent character traits to an offspring
what is a pure line
a group of individuals withing the same species who have the same trait that produce an offspring with the same trait.
what is crossbreeding
the exchange of gametes in sexual reproduction
what is a hybrid
an individual obtained by crossbreeding
what is a generation
group of offspring from the same parents
what is an allele
possible form of a gene. Different alleles have different nucleotide sequences
what is a homozygote
an individual who has alike alleles (homozygous alleles)
what is a heterozygote
an individual with two different alleles (heterozygous alleles)
what is a dominant allele
the allele that is expressed (in heterozygous individuals)
what is a recessive allele
the allele that is not expressed when a person is heterozygous. It only shows up when both alleles are recessive
what is a genotype
an individuals genetic heritance
what is a phenotype
the way the genotype of an individual expresses itself
what is the law of segregation of alleles
alleles for a specific traits seperate when gametes are formed. Each half receives one allele
what is the law of independant assortment
each allele seperates independently when more than one trait is being studied. the allele given to one gamete for one gene do not influence the other genes
what are punnett squares used for
to express genotype possibilities
what is genotypic ratio
the amount of one genotype relative to the total amount of possibilites
what is phenotypic ratio
the amount of one phenotype relative to the total amount of possibilities.
what is a monohybrid inheritance pattern
only one trait is being studied
what is a dihybrid inheritance cross
two traits are being studied
what is an incomplete inheritance pattern
when one allele is not completely dominant over the other, so a third phenotype with a combination of the two alleles is produced
what is codominance inheritance pattern
when no allele is dominant over the other, so both are expressed together.
what is sex-linked inheritance pattern
characteristics derived from x and y chromosomes
what is multiple allele inheritance pattern
three or more possible allele forms
what is a pedigree chart
illustration of the inheritance of traits in a family
