genetics Flashcards
define genetics
continuity
what does mitosis do
make diploid somatic cells
what does meiosis do
make haploid gametes
what is the human diploid number
46 or 23 pairs of chromosomes
what is the human haploid number
23 chromosomes
what don’t chromosomes not come in pairs of?
gametes or reproductive cells
mitosis and meiosis differences (3)
mitosis is a shorter process, makes diploid somatic cells, that are identical copies of DNA while meiosis is longer, makes haploid gametes, and crossing over results in new DNA combinations
who is mendel
father of genetics
describe what a true breeding plant is
a plant that always produces offspring with the same traits
outline how Mendel produced plants that had genes for both contrasting traits of a characteristic
First, he produced true breeding plants. He crossed pure plants for 2 contrasting traits. Then, the F1 generation began self-pollinating and reproducing.
define dominant
allele that is often expressed and will mask other alleles
define recessive
allele that is only expressed when present by itself
what are Mendel’s laws
Law of Segregation, Law of Independent Assortment, and Law of Dominance
explain the Law of Segregation
pair of genes are separated during formation of gametes
explain the Law of Independent Assortment
pair of genes are separated independently of one another during formation of gametes
Law of Dominance
some “factors” dominate or cover up others
why are Mendel’s law’s called “laws” and not “theories”
his laws have exceptions
define genes
segment of DNA on a chromosome that controls a hereditary trait
define allele
an alternative form of a gene
how did mendel’s F1 generation plants differ from his F2 generation plants?
F1 was a result of cross-pollination and F2 was a result of self-pollination.
what is a genome?
a map of our genes
how many different genotype
6 different genotypes
how many different phenotypes
4 types(A,AB,B,O)
how many alleles
3 (IA, IB, i)
how many genes
1
what are the 7 characteristics Mendel observed
seed shape, pod shape, flower color, seed color, pod color, and stem length
what are parents called
p generation
what is offspring called and what is offspring’s offspring called
f1 generation and f2 generation
define homozygous
two same alleles
define homozygous dominant
two dominant alleles
define homozygous recessive
two recessive alleles
define heterozygous
two different alleles
define phenotype
shown characteristics
define genotype
genetic makeup
define replication
exact duplicate copies of the entire DNA sequence
where and when does replication occur
in the nucleus during interphase
define transcription
mRNA copies part of the DNA sequence
where does transcription occur
in the nucleus/cytosol
define translation
mRNA code is translated into amino acid code
where does translation occur
in cytoplasm/ribosome
define codon
group of 3 nucleotides that code for 1 of the 20 different amino acids
what is the start codon in mRNA
AUG (methionine)
what are the stop codons
UGA, UAA, and UAG
what is the genetic flow
DNA -> mRNA transcription-> mature mRNA -> translation-> mRNA
define mutations
changes in structure/amount of DNA
what are the human bloods
red and white
what is Huntington’s disease and what is the pattern of inheritance?
deterioration of brain tissue in middle-age, autosomal dominant
what is cystic fibrosis and what is the pattern of inheritance?
mucus clogs lungs and pancreas, autosomal recessive
what is sickle cell anemia and what is the pattern of inheritance?
organ damage due to impaired blood flow, autosomal recessive
what is Tay-Sachs disease and what is the pattern of inheritance?
deterioration of the central nervous system, autosomal recessive
what is phenylketonuria and what is the pattern of inheritance?
infant’s brain fails to develop normally, autosomal recessive
what is marfan syndrome and what is the pattern of inheritance?
long limbs, loose joints, deformed vertebral column, crowded teeth, rupture of large arteries; autosomal dominant
what is breast cancer and what is the pattern of inheritance?
malignant tumors in breast tissue, autosomal dominant
what is hemophilia and what is the pattern of inheritance?
excessive bleeding due to blood clotting, X-linked recessive
what is genetic code
how a sequence of nucleotides corresponds to an amino acid
describe mRNA function and structure
carries genetic info from nucleus to cytosol, single chain
describe tRNA function and structure
carries specific amino acid, “T” shaped
describe rRNA function and structure
help form ribosome, globe shaped
how many different phenotypes are there for the human ABO blood type factor?
4 (A, AB, B, O)
how many different alleles are there for the human ABO blood type factor?
3 (A, B, O)
how many different genes are there for the human ABO blood type factor?
1
how many different genotypes are there for the human ABO blood type factor?
6 (IAi, IA IA, IA IB, IBi, IB IB, ii)
define amniocentesis
amniotic fluid around the fetus (physicians do this around 14-16 weeks)
what is the difference between chromatin and chromosomes
chromatin is spread out during interphase and chromosomes are coiled up
define complex character
characters that are strongly influenced by the environment and by genes
example of autosomal dominant
Breast cancer, Huntington’s disease, Marfan Disease
example of autosomal recessive
PKU, cystic fibrosis
example of co-dominance/ incomplete dominance
example of polygenetic traits
skin color
example of sex-linked
hemophilia
example of complex characteristics
skin color, intelligence
example of multiple alleles
