Chapter 4 - Chromosomes and Heredity Flashcards
transmission of genetic characteristics from parent to offspring
heredity
chart of 46 chromosomes laid out in order by size
karyotype
two members of each pair of the 23 pairs are called
homologous chromosomes
22 pairs of the 23 pairs of chromosomes are called
autosomes
the 1 pair of the 23 pairs of chromosomes is called
sex chromosome ( x and y)
know what a karyotype looks like and what it is
describes any cells with 23 pairs of chromosomes
diploid
describes cells containing half as many chromosomes as somatic cells; that is, sperm and egg cells
haploid
sperm and egg cells are called
germ cells
this restores diploid number to fertilized egg and somatic cells arise from it
fertilization
the location of particular gene on a chromosome
locus
different forms of gene at same locus on two homologous chromosomes
alleles
- masks recessive allele
- often produces protein responsible for visible trait
- represented by a capital letter
dominant allele
- represented by lowercase letter
- often codes for nonfunctional variant of protein
- corresponding trait only seen when recessive allele present on both homologous chromosomes
recessive allele
alleles an individual possesses for a particular trait
genotype
two types of genotypes
homozygous and heterozygous
individuals - two identical alleles for the trait
homozygous
individuals - different alleles for that gene
heterozygous
an observable trait
phenotype
a diagram showing possible genotype and phenotype outcomes from parents of known genotype
punnet square
an allele is _______ if it shows in the phenotype of an individual
expressed
they perform genetic testing and advise couples on probability of transmitting genetic diseases
genetic counselors
genetic makeup of whole population
gene pool
more than two allelic forms of gene
Ex: ABO blood
multiple alleles
both alleles equally dominant
Ex: AB blood
codominance
heterozygous individual shows phenotype intermediate btwn traits each allele would have produced alone
ex: red flower + white flower = pink flower
incomplete dominance
genes at two or more loci contribute to a single phenotypic trait
Ex: eye and skin colors; some cancers
polygenic inheritance
one gene produces multiple phenotypic effects
pleiotropy
this is a disorder resulting in mutation on chromosome 3 that blocks breakdown of tyrosine
alkaptonuria
carried on x or y chromosome; tend to be inherited by one sex more than the other
sex linked traits
why is color blindness more common in men than women
because men suck
just kidding…..
recessive color blindness allele on x, no gene locus for trait on y, so color blindness more common in men
percentage of population exhibiting expected phenotype
penetrance
these influence gene expression
ex: genes for melanin eye pigment can only be fully expressed if phenylalanine is in diet
environmental factors
are dominant alleles more common in gene pool than recessive alleles
no, some recessive alleles are more common
example of a dominant allele that’s rare in population
AB blood type
field examining nongenetic changes that alter gene expression and can be passed to offspring
-gene expression is changed without genetic mutation to base sequence
epigenetics
mechanism of epigenetic change in which methyl groups are added to DNA
- often silences the gene
- implicated in some forms of cancer
DNA methylation
what kind of tumors cause cancer
malignant tumors
- to give off cells that spread and seed the growth of tumors elsewhere
- what specific kind of tumor does this
- metastasize
2. malignant tumor
slow growing, encapsulated tumors
benign tumors
medical specialty dealing with tumors
oncology
growth of blood vessels by energy-hungry tumors
tumor angiogenesis
five types of cancers and where they are found
- carcinomas - in epithelial tissue
- lymphomas - in lymph nodes
- melanomas - in pigment cells of epidermis
- leukemias - in blood forming tissues
- sarcomas - in bone, other connective tissue or muscle
*know for test
environmental cancer causing agents
carcinogens
three types of carcinogens
radiation - UV rays, x rays
chemical - cigarette tar, food preservatives, industrial chemicals
viruses - HPV, hepatitis C, type 2 herpes simplex
what is the percentage of cancer that is hereditary
5-10%
these cause cell division to accelerate out of control
oncogenes
-mutated genes or silenced genes leave oncogene action unopposed
tumor-suppressor (ts) gene
-health tumor suppressor genes inhibit development of cancer
what is this
karyotype
what is this an example of
polygenic inheritance
is A or B the primary tumor
A
Is A or B the secondary metastatic tumor
B
The malignant cell penetrates blood or lymph vessel - 1, 2, 3, 4
1
Malignant cells travel to new sites - 1, 2, 3 or 4
2
Traveling cells escape vessel - 1, 2, 3 or 4
3
escaped malignant cells multiple and establish new tumors at new sites
1, 2 , 3 or 4
4
