8th Mitosis/Meiosis/Homeostasis
Organ system
A group of organs that work together to carry out a complex overall function.
Haploid
Having one set of chromosomes, as in sperm and egg.
Third step in mitosis
Metaphase.
Fifth step in mitosis
Telophase.
Metaphase
-Chromosomes line up randomly along the middle of the cell -Each chromosome's centromere attaches to a spindle fiber.
Interphase
-DNA breaks up into short chromosomes -Each chromosome makes an exact copy of itself -Each pair of chromosomes stays attached at the centromere (middle) -95% of the cell cycle DNA is not in chromosomes yet.
Prophase
-DNA coils up to form chromosomes -Chromosomes become visible -Nuclear membrane disappears -Threadlike spindle fibers stretch across the cells.
Telophase
-Nuclear membrane begins to form around the two sets of duplicated chromosomes. -The cell pinches apart in the middle.
Anaphase
-Spindle fibers pull each pair of chromosomes apart and toward opposite ends of the cell.
Problem Answer 2,20
A cell with 20 chromosomes undergoes mitosis. How many daughter cells are created? And each daughter cell has ___ chromosomes?
Tissue
A group of connected cells that have a similar function.
Organ
A structure that consists of two or more types of tissues that work together to do the same job.
Allele
Alternate form of a gene.
Fourth step in mitosis
Anaphase.
The Cell
Carries out basic life processes that allow the body to survive.
Zygote
Cell that forms when a sperm and egg unite; the first cell of a new organism.
Level I of organization in the human body
Cell.
Hormone
Chemical messenger molecule.
Chromosome
Consists of two daughter cells.
Nervous system
Controls virtually all body activities.
Prophase I
Crossing over between nonsister chromatids happens in this phase.
Cytokinesis
Divided cell forms two daughter cells and begins in telophase.
Mitosis
Division of the nucleus. All living things grow and repair themselves (the process of cell division).
Four basic types of tissue
Epithelial, muscle, nervous, and connective.
Crossing-over
Exchange of DNA between homologous chromosomes that occurs during Prophase I of meiosis.
Product of meiosis
Four genetically unique haploid cells.
Diploid
Having two sets of chromosomes.
First step in mitosis
Interphase.
Connective tissue
Made up of cells that form the body's structure.
Muscle tissue
Made up of cells that have the unique ability to contract, or become shorter.
Epithelial tissue
Made up of cells that line inner and outer body surfaces, protects the body and its internal organs, secretes substances such as hormones, and absorbs substances such as nutrients
Nervous tissue
Made up of neurons, or nerve cells, that carry electrical messages.
Gametes
Mature haploid cells formed in animals through meiosis.
Level 4 of organization in the human body
Organ system.
Level 3 of organization in the human body
Organ.
Level 5 of organization in the human body
Organism.
Homologous chromosomes
Pair of chromosomes that have the same size and shape and contain the same genes, but different alleles.
Meiosis
Process of cell division during which the chromosome number is halved in order to produce gametes.
Sexual reproduction
Process of forming a new individual from two parents.
Second step in mitosis
Prophase.
Gamete
Reproductive cell, such as sperm or egg.
Negative feedback
Response to a stimulus that keeps a variable close to a set value.
Positive feedback
Response to an event increases the likelihood of the event to continue.
Spindle
Structure that helps separate the sister chromatids during mitosis; also separates homologous chromosomes during meiosis.
Homeostasis
The ability of the body to maintain a stable internal environment despite a changing environment - primarily maintained through negative feedback, when a response to a stimulus keeps a variable close to a set value.
Cells
The most basic parts of an organism.
Four haploid cells
These form at the end of telophase II and cytokinesis.
Level 2 of organization in the human body
Tissue.
