Biology Chapter on Chromosomes and Genes

threadlike structures made of DNA molecules that contain the genes

genetic material that is in every cell of your body. Pair of nucleotide bases

contain instructions for making protein that are building blocks for your body (e.g., eye color, hair color)

46 chromosomes in 2 pairs of 23 gametes

first 22 pairs of chromosomes

Chromosomes that determine the sex of an individual (23rd pair)

reproductive cells that have 23 chromosomes each

fertilized egg

complete set of genes the make up a person's heredity

An organism's physical appearance, or visible traits. created from genotype and environment

mixing sperm and egg together in a lab dish a placing a few of the fertilized eggs in the month's uterus. 1/3 attempts suceed

about 25000 genes. chromosome 1 has the most, y chromosome has the least

An international collaborative effort to map and sequence the DNA of the entire human genome. used 10 men and 10 women in buffalo NY. 75%came from a male donor.

big science

personalized treatment, inherited diseases, understanding human evolution

Different forms of a gene, come in pairs

two identical alleles for a trait

different alleles for that gene

one whose trait always shows up in the organism when the allele is present

An allele that is masked when a dominant allele is present. person must inherit two recessive alleles, one from each parent, to have a recessive phenotype

Situation in which one allele is not completely dominant over another allele

Curly hair, dark hair, thick lips, dimples

Straight hair, light hair, thin lips, no dimples

Dominant alleles always show up even if there is only one copy and recessive alleles only show up if both copies of the gene are recessive

If the recessive allele is for blue eyes, you'll only have blue eyes if you inherit the blue-eye allele from both parents

Hemophilia is a disorder where the blood does not clot easily and sufferers can bleed severely with minor injuries, the gene is carried on the x chromosome

extra 21 chromosome. odds go up with mothers age

the study of how genes and the environment influence behaviour

combined effect of two or more genes on a single character

you have aabbcc and capital letter is a dominant trait. this dominant trait is being tall, there are many options a person have. aabbcc is rare AABBCC is also rare

identical- come from one fertilized egg.

fraternal- look different. twins come from two separate eggs fertilized by two separate sperm.

the same genotype can produce a range of phenotypes in reaction to environment

the continuous interplay between genes and multiple levels of the environment (from cells to culture) that drives development

estimate the extent to which differences between people reflect heredity. example: 50% of the differences in cognitive ability is due to heredity

the proportion of variation among individuals that we can attribute to genes

specific groups of people (not an individual) in specific environments

mechanisms that cells use to control gene expression. A chemical reaction in the body in which a small molecule called a methyl group gets added to DNA.

deliberately seeking environments that fit one's heredity First childhood, increasingly so throughout the development

those environmental factors that are experienced by all relevant members of a household

unique aspects of a person's environment and experience that are not shared with family members