STAAR Notebook 3

Cell Cycle and Mitosis

The purpose of cell division is to create two identical daughter cells. Multicellular organisms grow through repeated cell divisions. Full grown humans contain trillions of cells!

Interphase contains the G1, S and G2 phases of cell division. 90% of the cell cycle is spent in interphase! Interphase contains the G1, S and G2 phases of cell division. Checkpoints occur at different stages of the cell cycle to insure healthy daughter cells! The S Phase is when cells synthesize a new set of DNA! During the S Phase, DNA is replicated so that the cell contains 2 complete sets!

Mitosis is the process that allows each daughter cell to contain a complete set of DNA. Prophase Metaphase Anaphase Telophase Spindle fibers attach to chromosomes and line them up Spindle fibers separate the chromosomes into two sets Nuclei reform around each set of DNA Chromosomes condense and nucleus dissolves Cytokinesis completes cell division. The cell is split apart into two daughter cells.

STAAR Questions Cell Cycle and Mitosis

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Cell Differentiation

Every cell in your body contains a complete set of DNA. Remember: Gene expression is a regulated process. Cells can turn genes ON or OFF so that only the genes needed by a cell are activated! Stem cells are undifferentiated cells that can become different specialized cells. Chemical signals and other environmental factors direct the differentiation of stem cells.

STAAR Questions Cell Differentiation

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Disruption to the Cell Cycle and Cancer

Tumor Cell division is a regulated process, but disruptions to the cell cycle can occur. When cells divide too rapidly, they can form tumors. Tumor Oncogenes are mutated genes that cause normal cells to become cancer cells. These cancer cells repeat the cell cycle continuously! The drugs used to treat diseases like cancer target the cell cycle to stop cells from reproducing uncontrollably.

Disruptions to the Cell Cycle and Cancer STAAR Questions Disruptions to the Cell Cycle and Cancer

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Meiosis

Organisms that sexually reproduce have 2 copies of each chromosome. Pairs of chromosomes with equivalent genetic information are called homologous chromosomes. During meiosis, homologous chromosome recombine through a process called crossing-over. Meiosis is the process that creates gamete cells like sperm and egg cells. Meiosis increases genetic variations in a species. This increased genetic diversity can help a species adapt! Meiosis reduces the number of chromosomes in gamete cells. Gametes have 1/2 the chromosomes.

STAAR Questions Meiosis

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Body Systems

CIRCULATORY SYSTEM RESPIRATORY SYSTEM The respiratory system absorbs oxygen gas (O2) into the body which is needed for cellular respiration. The respiratory system also releases carbon dioxide gas (CO2) from of the body. The circulatory system distributes oxygen and nutrients to cells all over the body and carries carbon dioxide and waste away from the cells.

NERVOUS SYSTEM DIGESTIVE SYSTEM The digestive system breaks down food and absorbs nutrients needed for the growth and repair of the body. It is aided by bacteria that live in the intestines and help break down complex nutrients. The nervous system responds to stimuli from inside and outside the body. It controls the body’s actions and its responses to any changes. All five senses are part of the nervous system.

MUSCULAR SYSTEM SKELETAL SYSTEM The muscular system is responsible for all of the body’s movements, both voluntary (jumping, chewing, walking, etc.) and involuntary (breathing, stomach churning, heart pumping, etc.). The bones of the skeletal system provide the structure and support needed for movements and protect your internal organs. Bones store minerals and produce blood cells in the bone marrow.

INTEGUMENTARY ENDOCRINE SYSTEM SYSTEM Hormones are chemical signals produced by the glands of the endocrine system. Hormones help maintain homeostasis and control growth and development. Skin is the primary organ of the integumentary system. It serves as a protective barrier around your body preventing water loss and helping to control body temperature.

IMMUNE SYSTEM LYMPHATIC SYSTEM The immune system is made of white blood cells and antibodies that protect your body from infection. HIV attacks a special type of white blood cell called a T helper cell. The lymphatic system removes fluid from around cells and returns it to the circulatory system. As this fluid passes through lymph nodes, white blood cells attack and kill parasites found in the fluid.

REPRODUCTIVE SYSTEM EXCRETORY SYSTEM The reproductive system produces the gamete cells needed for sexual reproduction inside the gonads (testes or ovaries). The male gamete cells are called sperm, and the female gamete cells are called eggs. The excretory system removes waste from the body and helps the body maintain homeostasis by preventing the buildup of excess fluid and solid material within the body.

STAAR Questions Body Systems

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Levels of Organization

CELL TISSUE ORGAN ORGANISM ORGANISM POPULATION COMMUNITY ECOSYSTEM ORGAN SYSTEM Cells are the basic building blocks of every organism. Tissues are groups of specialized cells. Organs are made of tissues and perform specific functions in the body. Organ systems are groups of organs working together to perform a function. Organisms are complete living things. ORGANISM POPULATION COMMUNITY ECOSYSTEM An organism is a single, complete living thing. (Organism = 1 living thing) A population is all the members of a single species living in an area. A community contains all of the different living things in an area. An ecosystem contains all of the living and nonliving components in an area.

Levels of Organization STAAR Questions Levels of Organization

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Quiz Next Class!!!!!!!!!!!!!! Study STAAR 3 for Quiz next class! Will count double in the gradebook!