The two major groups of specialized cells in your body are _______ and ________. • Somatic cells and germ cells
______ cells, also called body cells, make up most of your body tissues and organs. • Somatic cells
DNA is passed on to offspring by ____ ___. • Germ cells
Gametes are ____ cells. • sex
Chromosome number does not seem to be related to the _______ of an organism. • complexity
Humans receive 23 chromosomes from the _____ and 23 from the _____. • Mother, father
In humans, each pair of chromosomes is referred to as a ________ ____. • Homologous pair
Homologous means……. • Having the same structure
A number has been assigned to each homologous pair, ordered from _____ to _____. • Largest to smallest
Chromosome pairs 1-22 make up your ______. • autosomes
These chromosomes are not directly related to the sex of an organism. • autosomes (1-22)
X and Y chromosomes are not _______. • homologous
______ _______ involves the fusion of two gametes that results in offspring that are a genetic mixture of both parents. • Sexual reproduction
The actual fusion of an egg and sperm cell is called _______. • fertilization
When fertilization occurs, the nuclei of the egg and sperm cell fuse to form one _____. • nucleus
Egg and sperm cells only have half the usual number of ______. • chromosomes
Body cells are ____, meaning that a cell has two copies of each chromosome. • diploid
Gamete cells are _____, meaning that one cell has one copy of each chromosome. • haploid
The sex of an individual is determined by the _____. • Male (for humans)
Increasing the number of sets of chromosomes can give rise to a new _____. • species
4 copies of each chromosome. • A condition called tetraploidy
Germ cells in human reproductive organs undergo _____ to form gametes. • meiosis
______ is a form of nuclear division that divides a diploid cell into haploid cells. • meiosis
What are some of the differences between mitosis an meiosis? • In mitosis, DNA is copied once and divided once. In meiosis, DNA is copied once but divided twice. • In mitosis, daughter cells are genetically identical to the parent cell. Meiosis makes genetically unique haploid cells from a diploid cell. • Mitosis is used for growth, development, and repair. Takes place throughout life. Meiosis, however, takes place only at certain times. • Mitosis is involved in asexual reproduction, meiosis is involved in sexual reproduction.
Where are germ cells located in the human body? • Ovaries and testes • What is the difference between an autosome and a sex chromosome? • Autosomes, chromosomes 1-22, are not directly related to the sex of an organism.
Is the cell that results from fertilization a haploid or diploid cell? Explain. • Each cell has only one copy of each chromosome. It takes the combination of an egg and sperm cell to make the 46 human chromosomes…..so haploid.
Does meiosis or mitosis occur more frequently in your body? • Mitosis, it is responsible for growth, development, and repair. • Meiosis is responsible for reproduction.
_______ is a form of nuclear division that creates four haploid cells from one diploid cell. • Meiosis • Meiosis _______ chromosome number and creates genetic _________. • reduces,diversity
Each half of a duplicated chromosome is called a ________. • Chromatid • ______ ______ are the duplicated chromosomes that remain attached by the centromere. • Sister Chromatids
______ ______ are divided during meiosis I. ____ ______ are not divided until meiosis II. • Homologous chromosomes • Sister chromatids
Before meiosis begins, _______ has already been copied. • DNA • What are the 4 stages of meiosis I? • Prophase I • Metaphase I • Anaphase I • Telophase I
Identify the phase in meiosis I. • The nuclear membrane breaks down centrosomes and centioles move to opposite sides of the cell. Spindle fibers assemble Homologous chromosomes pair up • Prophase I
Identify the phase in Meiosis I • Homologous chromosome pairs are randomly lined up along the middle of the cell by spindle fibers. • Metaphase I
Identify the phase in Meiosis I • Paired homologous chromosomes separate and move to opposite sides of the cell. • Anaphase I
Identify the phase in Meiosis I • The nuclear membrane forms, the spindle fibers disassemble, and the cell undergoes cytokinesis. • Telophase I
Identify the phase in Meiosis II • The nuclear membrane breaks down, centrosomes and centrioles move to opposite sides of the cell, spindle fibers assemble. • Prophase II
Identify the phase in Meiosis II • Spindle fibers align the 23 chromosomes at the cell equator • Metaphase II
Identify the phase in Meiosis II • The sister chromatids are pulled apart from each other and move to opposite sides of the cell. • Anaphase II
Identify the phase of Meiosis II • Nuclear membranes form around each set of chromosomes at opposite ends of the cell, spindle fibers break apart, the cell undergoes cytokinesis, and four haploid cells are produced. • Telophase II
What is the major difference between Metaphase I and Metaphase II? • In metaphase I, pairs of homologous chromosomes line up at the equator. In metaphase II, the chromosomes are not paired.
What is the major difference between Anaphase I and Anaphase II? • Sister chromatids remain together in Anaphase I but separate in Anaphase II.
___________ is the production of gametes. • Gametogenesis