Bio 1 EXAM 3

Sexual reproduction

two parents give rise to offspring that have unique combinations of genes

Asexual reproduction

single individual passes genes to its offspring without the fusion of gametes (creates clones)

Genome

All the genetic material in a cell

Chromatin

mixture of DNA, RNA, and proteins found in the nucleus of eukaryotic cells

Somatic cells

Non-reproductive cells

Gametes

Reproductive cells

Mitosis

Yields 2 genetically identical daughter cells (eukaryotes)

Cytokinesis (with respect to animal/plant cells)

Final stage of division where cells split (animals = cleavage furrow) (plant cells = cell plate)

Meiosis

yields four non-identical haploid daughter cells

Mitotic phase

replicated DNA and cytoplasmic components are separated, and the cytoplasm is partitioned

Interphase

growth and copying of chromosomes in preparation for cell division (about 90% of the cell cycle)

Sister chromatids

Formation of identical pairs of chromosomes connected at the centromere

centromere

Center indent in chromosomes

Kinetochore

Protein that allows spindle microtubules to attach to centromere in cell division

Metaphase plate (equatorial plate)

an imaginary structure midway between the spindles two poles

Cell cycle control system

Checkpoints in interphase that ensure proper cell division (G1, S, G2, M)

Growth factors

released by cells that causes other cells to divide

Density-dependent inhibition

Crowded cells (cells that touch each other) stop dividing

Benign

slow-growing tumors with defined borders that stays in one location

Malignant

fast-growing tumors with irregular borders that can invade other tissues

Metastasize

spread to other sites in the body by metastasis

metastasis

the development of secondary malignant growths at a distance from a primary site of cancer

Heredity

the transmission of traits from one generation to the next

Diploid (2n)

2 sets of chromosomes

Haploid (1n)

1 set of chromosomes

Alleles

different versions of the same gene at its locus

Locus

Specific location of a gene on a chromosome

Fertilization

union of haploid gametes (n = 23 chromosomes in humans)

Zygote

fertilized egg ( Diploid ; 2n = 46)

Crossing over

exchange of genetic material between non-sister chromatids of homologous chromosomes

Chiasmata

site of crossing-over

Random fertilization

any sperm can fuse with any unfertilized egg

True-breeding varieties

organisms that consistently produce offspring with the same phenotypic traits as the parents when self-pollinated or crossed with others of the same variety

P generation

Parent generation

F1 generation

offspring produced by crossing two parents

F2 generation

produced by self pollination of the F1 (grandchildren)

Homozygous

the two alleles at a particular locus may be identical

Heterozygous

the two alleles at a particular locus may differ

Phenotype

Physical appearance

Genotype

Genetic makeup

F1 dihybrids

heterozygous; offspring from 2 true-breeding parents (homozygous) with differing phenotypes

Consanguineous mating

mating between close relatives

Complete dominance

phenotypes of the heterozygote and dominant homozygote are identical

Incomplete dominance

phenotype of F1 hybrids is somewhere between the phenotypes of the two parental varieties

Codominance

Both alleles are fully expressed

Barr body

condensed inactive X chromosome

Pleiotropy

one gene affects multiple phenotypic characteristics

Nondisjunction

pairs of homologous chromosomes do not separate normally during meiosis

Aneuploidy

fertilization of gametes in which nondisjunction occurred

Monosomy

only one copy of a particular chromosome (2n-1)

Trisomy

three copies of a particular chromosome (2n+1)

Polyploidy

an organism has more than two complete sets of chromosomes

Polygenic inheritance

an additive effect of two or more genes on a single phenotype

Epistasis

A gene at one locus alters the phenotypic expression of a gene at a second locus

Pedigree

a family tree that describes the interrelationships of parents and children across generations

Carriers

heterozygous individuals who carry the recessive allele but are phenotypically normal

How does cancer relate to Density-dependent inhibition?

Cancer damages the inhibition of touching cells, causing them to grow erratically and continuously

3 mechanisms of genetic variation

Independent assortment of chromosomes, Crossing over, Random fertilization

What organism did Mendel use to determine the first patterns

garden peas

Why can Consanguineous mating be detrimental to offspring

If a rare allele that codes for a disorder is present in a generation, inbreeding increases the likelihood of two individuals with the same rare allele mating

What are the 4 types of chromosome structural changes?

Deletion, Duplication, Inversion, Translocation

effects of inversions

balance of genes is normal but phenotype may be impacted by changes in gene expression

effects of deletions

usually fatal

effects of Duplications and translocations

tend to be harmful

Prophase

chromatin condenses / asters form and anchor centrosomes at poles / nuclear membrane disassociates / Centrosomes move apart by lengthening microtubules

Metaphase

Kinetochore proteins attach to attach to microtubules / non kinetochore proteins span cell / “blah” aligns to separate on the metaphase plate

Prometaphase

Chromatin continues to condense / kinetochore microtubules attach / centrosomes continue to move to opposite poles

Anaphase

Kinetochore attached microtubules shorten / non kinetochore proteins elongate / chromosome pairs separate / cell elongates

Telophase

Chromatin decondenses / asters disassociate / nuclear membrane reforms / cell forms cleavage furrow in animals and forms a cell plate in plants/fungi (cytokinesis begins)