Unit 5: Hereditary

AP BIO

what is haploid vs diploid?

Haploid refers to cells that contain a single set of chromosomes (n), while diploid refers to cells that contain two sets of chromosomes (2n), one from each parent.

what are gametes?

• haploid sex cells

  • each parent contributes a gamete with one set that will be paired with another parent to form diploid cell, zygote

who is Gregor Mendel?

• the father of genetics bc he discovered it

  • found that traits are influenced by one or more genes

  • the position of gene on chromosomes is called locus

• diploid organisms have two copies of genes on each homologous chromosomes

  • humans have 23 pairs of homologs

  • homologs are the same size, shape and have the same genes but contain different version of the genes called alleles so they contain diff genetic sequences

what is the law of dominance?

One trait masks the effects of another trait.

what is the law of segregation?

Each pair of homologous chromosomes splits independently, so

the alleles of different genes can mix and match.

what is law of independent assortment?

the alleles of two (or more) different genes get sorted into gametes independently of one another. In other words, the allele a gamete receives for one gene does not influence the allele received for another gene

what are non mendelian linked genes?

• sometimes genes on the same chromosomes stay together moving as a group and will be inherited together they cannot segregate independenlty

  • this violates law of independent assortment

• forms recombinant offspring

what are sex linked traits?

• humans have 23 pairs of chromosomes, 22 being autosomes that code for diff traits. the other pair is sex and determines the sex

  • blindness and hemophilia and sex linked traits

what are barr bodies?

• an x chromosomes that is condensed and visible. in every female cell, one x is activated while the other is deactivated during embryonic development

• the x deactivated is randomly chosen in each cell

• it is passed down to daughter cells

what is incomplete dominance?

when traits blond like red and white and heterozygous being pink

what is codominance?

expression of both alleles like pink and white = pink and white

example is AB blood type

what is polygenic inheritance?

multiple genes are involved in determining a single trait, resulting in a continuous range of phenotypes. Traits like height, skin color, and eye color are often influenced by several genes, leading to variations in those traits.

what is non nuclear inheritance?

• there is genetic material in the mitochondria

• the mitochondria is provided by the egg so the genetic material is inherited through the maternal line

• in plants the mitochondria is provided by the ovule and are maternally inherited

what are pedigrees?

traits that skip generations are usually recessive

traits that appear in more than one sex than the other is sex linked

if the dad has it, and all the daughters get it its recessive and vice versa

what are the environmental effects on traits?

Environmental factors, such as climate, nutrition, and exposure to toxins, can influence the expression of genetic traits, leading to variations in phenotype even among individuals with the same genotype.

Give an overview of meiosis?

• production of gametes

• in males the gonads are the testes while females have ovaries

• produces variation

what are the steps of meiosis?

1. prophase 1 is when chromatin condense and sister chromatids align. crossing over occurs

2. metaphase 1 is where homologous chromosomes align on the metaphase plate. independent assortment occurs

3. anaphase 1 is where the homologous chromosomes separate to opposite poles

4. telophase 1 is where the nuclear envelope forms around the haploid daughter cells

5. prophase II is where chromatin condense and sister chromatids align

6. metaphase II is where sister chromatids align on plate

7. anaphase II is where sister chromatids separate

8. telophase II is nuclear envelope forming around haploid daughter cells

what is downs syndrome?

Down syndrome is a genetic disorder caused by the presence of an extra copy of chromosome 21, leading to developmental delays, distinct physical features, and potential health issues.

what is Klinefelter syndrome?

Klinefelter syndrome is a genetic condition where a male is born with an extra X chromosome, resulting in XXY instead of the typical XY configuration. This can lead to symptoms such as reduced testosterone levels, infertility, and physical differences such as taller stature.

what is turner syndrome?

Turner syndrome is a genetic condition that occurs in females when one of the X chromosomes is missing or partially missing, resulting in a 45,X karyotype. It often leads to short stature, delayed puberty, and infertility, along with various other health issues.

what is gametogenesis?

• when sperm cells are produced its spermatogenesis

  • produced 4 sperm cells for each diploid cell

• if egg cell/ovum is produced, its called oogensis

  • produced only one ovum and the other three are polar bodies that degenerate