Biology Chapter 8 Review - Basic Genetics

chromosome

a structure consisting of DNA and supporting proteins (also found in a cell's nucleus.)

gene

segment of DNA that codes for a specific protein, resulting in a particular trait.

chromatin

genetic material of eukaryotic cells consisting of DNA and associating proteins.

histones

any of a group of basic proteins found in chromatin.

chromatid

Each half of the chromosome

centromere

this joins two halves of a chromosome

sex chromosomes determine what?

gender

male and female chromosomes?

XX- female
XY- male

number of chromosomes

general number:23

number of autosomes

22 (autosomes do not determine sex of an organism)

karyotype

picture of ordered chromosomes

chromosomes pairs are??

homologous

diploid

cells that have homologous pairs

haploid is represented by..

N

diploid is represented by..

2n

cell cycle

process of cell growth that leads to cell division for many cells

Interphase

the phase where the cell spends most of its time. The cell grows and the DNA duplicates, and the cell prepares itself to divide.

mitosis

phase of the cell cycle where a cell's duplicated DNA is divided into two identical sets

cytokinesis

process during cell division where the cytoplasm of a cell is divided between the two new daughter cells.

prophase

the mitotic spindle forms and the chromosomes become visible

metaphase

the chromosomes are aligned in the middle of the cell

anaphase

the chromosomes are pulled toward the centromeres

telophase

the nuclei begin to reform, the mitotic spindle dissembles, and cytokinesis begins

cytokinesis

the cell completes its division in two cells.

Meiosis

The process by which haploid gametes are produced from diploid cells.

prophase 1

the tetrads exchange genes and crossing over occurs

metaphase 1 and 2

chromosomes are aligned

anaphase 1 and 2

chromosomes are pulled toward the centromeres

(in meiosis) telophase 1 and cytokinesis

nuclei begin to reform

prophase 2

chromosomes do not duplicate

metaphase 2

chromosomes are aligned

anaphase 2

chromosomes pulled toward the centromeres

telophase 2 and cytokinesis

end up with 4 cells that are genetically different from each other

gametes

(reproductive cells) are haploid

zygote

formed by the union of two gametes. a diploid cell is formed that is genetically different from either parent

What is the outcome of mitosis?

Leads to genetically identical cells.

How many cells are generated by mitosis after one cell division?

two diploid cells.

Does mitosis involve homologous pairs of chromosomes?

Yes, it has homologous pairs of separate chromosomes.

What type of reproduction does mitosis represent?

Asexual reproduction.

What type of cell division leads to genetically different cells?

Meiosis

How many haploid cells are generated by meiosis?

4 haploid cells

What structure is formed by homologous pairs of chromosomes during meiosis?

Tetrads

What is the role of meiosis in sexual reproduction?

It allows two haploid cells to join and form a genetically different diploid zygote.

What is a similarity between mitosis and meiosis?

Both are a form of cell reproduction.

What type of cell do both mitosis and meiosis begin with?

Both begin with a tetraploid cell.

How is Meiosis 2 related to mitosis?

Meiosis 2 is almost the same process as mitosis.

heredity

the passing of traits from one generation to another

Mendel experimented on..

pea plants

three principles of genetics

1. Principle of Heredity
2. Principle of Segregation
3. Principle of Independent Assortment

principle of heredity

Each parent plant contributes a "factor" for each trait

dominant trait

the characteristic that is expressed even in the presence of the recessive genes

recessive trait

a characteristic that is expressed only in the absence of a dominant allele.

purebred =

homozygous

hybrid =

heterozygous

allele

different forms a gene can have

Genotype

genetic makeup

Phenotype

the physical expression of a trait.

principle of segregation

says that the factors that determine a trait must separate into the reproductive cells

principle of independent assortment

states that traits mix and match freely

punnet squares

used to show the different ways that alleles can segregate. (shows possibilities and probablities)

what is a dominant gene expressed by?

a capital letter

what is a recessive gene expressed by?

a lowercase letter

monohybrid cross

it tests only one set of alleles

dihybrid cross

it tests two sets of alleles

pedigree

a family history that charts a hereditary trait through past generations

incomplete dominance

a blend of dominant and recessive traits (black + white = gray)

codominance

both alleles that are inherited are expressed. (black + white = spotted pattern including both colors)

what traits have multiple alleles?

human blood types

polygenic inheritance

two or more genes working together to express a trait (ex. human skin color)

sex linked traits

are controlled by the sex chromosomes (ex. calico cats, red-green colorblindness)

carrier

an individual who carries an allele but does not express it

gene expression

the process in which genetic information is activated to make a genetic product. (controlled by 2 main factors)

What are promoters in genetics?

Little sequences of DNA that come before each gene.

What is the function of promoters?

They tell the RNA polymerase where to bind and begin copying the gene into a strand of mRNA.

TATA box

common promoter that binds to a group of transcription proteins, which are attached to RNA polymerase

enhancers and silencers

they tell the promoter what to do and work with regulatory proteins

introns

non-coding sections of DNA

extrons

coding sections of DNA

hormone activated traits

responsible for puberty, when different genes are activated, resulting in different developments between the sexes.

totipotent genes

can turn into any kind of cell (found in zygote or embryo)

pluripotent genes

can produce many, but not all kinds of cells

homeotic genes

provide a map for the baby's structure. they work to produce each kind of cell needed.

embryonic stem cells

come from an embryo and are totipotent

somatic stem cells

come from an adult are are pluripotent. (also found in fetuses of babies)

organization of genetic material from largest to smallest.

DNA, gene, expression