Bio chap 13

“pro”

Before or first

“meta”

Middle

“ana”

Away or apart

“telo”

Competition or end

What do children inherit from their parents?

Genes

Genes

Units or heredity and are made up of segments of DNA

Gametes

Pass genes to the next generation via reproductive cells

What is most DNA packaged into?

Chromosomes

Somatic cells

All cells of the body except gametes in their precursors

How many chromosomes do humans have?

46

Locus

A genes specific position along a chromosome

Asexual reproduction

A single individual passes all of its genes to its offspring without fusion of gametes

Clone

Group of genetically identical individuals from the same parent

Sexual reproduction

Two parents give rise to offspring that have unique combination of genes inherited from the two parents

Life cycle

The generation-to-generation sequence of stages in the reproductive history of an organism

Human somatic cells have how many pairs of chromosomes?

23

Karyotype

Is an ordered display of the pairs of chromosomes from a cell

Homologous chromosomes (homologs)

The two chromosomes in each pair

Desc. of homologous chromosome pairs

• The same length and shape

• Carry genes controlling the same inherited characters

Sex chromosomes

Determine the sex of the individual, are called X and Y

Female sex chromosome

XX

Male sex chromosome

XY

Autosomes

The remaining 22 pairs of chromosomes

Each pair of homologous chromosomes includes

One chromosome of each parent

Diploid cell (2n)

Two sets of chromosomes

Diploid number of humans

46 (2n = 46)

DNA synthesis

Each chromosome is replicated

Each replicated chromosome consists of?

Two identical sister chromosomes

Haploid

A gamete contains a single set of chromosomes

Privet shrubs and humans each have a diploid number of 46 chromosomes per cell. Why are the two species so dissimilar?

The two species have appreciably difference genes

Fertilization

The union of gametes

Zygote

The fertilized egg

How many sets of chromosomes does a zygote have?

One

What do zygotes produce by mitosis?

Somatic cells and develops into an adult

What do ovaries and testes produce at sexual maturity

Haploid gametes

Gametes are the only types of human cells produced by?

Meiosis

Meiosis result

One set of chromosomes in each gamete

Alternate in sexual life cycles to maintain chromosome number

Fertilization and meiosis

Three main types of sexual life cycles

• Diplotonic (animal)

• Haplodiplotonic (plant and algae)

• Haplotonic (fungi and protist)

Diplotonic cycle (animals)

The multicellular organism is diploid, meaning its cells have two complete sets of chromosomes

Haplodiplotonic cycle (plants and algae)

Organisms spend time in both multicellular haploid and multicellular diploid stages

Haplotonic cycle (fungi and protists)

The dominant multicellular organisms is haploid

Gametes fuse to form?

A diploid zygote that divides by mitosis to develop into a multicellular organisms

The only haploid cells in animals

Gametes

Plants and some algae exhibit

An alternation of generation

An alternation of generations

Includes both a diploid and haploid multicellular stage

Sporophyte

Diploid organism that makes haploid spores by meiosis

What do gametophytes make by mitosis?

Haploid gametes

Each spore grows by mitosis into a haploid organism called a

Gametophyte

Fertilization of gametes results in?

A diploid sporophyte

The zygote produces what by meiosis?

Haploid cells

Sexual reproduction

Asexual reproduction

In all three life cycles, what contributes to genetic variation in offspring?

Halving and doubling of chromosomes

Only _____ cells can undergo meiosis

diploid

Like mitosis, meiosis is preceded by?

The replication of chromosomes

Meiosis takes place in two consecutive cell divisions called?

Meiosis and I and II

Meiosis I and II result in?

Four daughter cells

Each daughter cell has only half as many chromosomes as the?

Parent cell

Why is it more practical to prepare karyotypes by viewing somatic diploid cells rather than haploid gametes?

Both sets of chromosomes, which are present in somatic diploid cells, need to be examined

Chromosomes during interphase

They duplicate

Sister chromatid cohesion

The resulting sister chromatids are closely associated along their lenghts

Sister chromatids are sorted into?

Four haploid daughter cells

Meiosis I

Homologous chromosomes separate and haploid cells with duplicated chromosomes

Meiosis II

Sister chromatids separate and haploid cells with unduplicated chromosomes

Meiosis I phases

• Prophase I

• Metaphase I

• Anaphase I

• Telophase I and cytokinesis

Meiosis II phases

• Prophase II

• Metaphase II

• Anaphase II

• Telophase II and Cytokinesis