1 st Quarter Biology STAR Review

Scientific Method 1.Observation is made using one of your 5 senses. 2.A hypothesis is a proposed explanation for the way something functions. 3.A prediction forecasts the outcome of an experiment if the hypothesis is true. -

Scientific Method cont. 4. An experiment tests the hypothesis and the predictions. 5. Data are analyzed and conclusions made. 6. Communication to peers and public.

Enzymes Speed up reactions without altering the reaction Must have substrate match perfectly in order to become active Very sensitive to temperature, pH, and salinity

Cell Theory 1. all living things are composed of 1 or more cells 2. cells are the basic units of structure and function in an organism 3. cells come only from the reproduction of existing cells

Prokaryotic cells cells without a nucleus (bacterial cells)

Eukaryotic cells cells with a nucleus (animal cells, plant cells)

Organelles Internal organization – cells have internal structures that carry out their life processes Organelles – a cell component that performs specific functions for a cell

Organelles In animal cells…

Cell Membrane Composed of a lipid bilayer –contains several kinds of proteins that “float” along the bilayer Selectively permeable –some things can easily cross the membrane and others cannot cross at all

Cytoplasm the jello between the cell membrane and organelles

mitochondria transfers energy from organic compounds to ATP (stored energy) Has two membranes more mitochondria in cells that use the most energy –Ex. Muscle and heart cells

Ribosome makes proteins Found in the cell: Attached to the Endoplasmic Reticulum Free floating in cytoplasm

Endoplasmic Reticulum  – Transport system that moves materials which have been made throughout the cells  Like an assembly line

Golgi Apparatus looks a lot like ER, except has vesicles modifies proteins for export by the cell packages substances produced by the cell

Protein Transport

Lysosome digests molecules, old organelles, and foreign substances (“clean up crew”)

Cilia and Flagella hair like organelles that extend from the surface of the cell assist in movement

Nucleus  Control center of cell, contains DNA, creates ribosomes

More Organelles… In plants…

Plant Cells plants contain most of the same organelles as other eukaryotic cells plus 3 additional ones –Cell Walls –Vacuoles –Chloroplasts

Cell Wall a rigid layer on the outside of the cell membrane supports and protects the plant composed of long chains of cellulose

Vacuoles filled with water and stores enzymes and metabolic wastes Much larger than animal vacuoles

Chloroplast convert sunlight to energy like mitochondria, they have two membranes chloroplast – contain sacs called thylakoids –contain pigments that give the flower/plant their color

Multicellular Organization

Levels of organization Tissues – groups of cells that carry out a specific function Organs –several types of tissues that interact to perform a specific function Organ system – a group of organs that work together to perform a set of related tasks

Transport Moving materials into or out of the cell through the cell membrane

Passive Transport Does NOT require any energy Moves from an area of high to low concentration 3 kinds –Diffusion –Osmosis –Facilitated Diffusion

Diffusion Movement of molecules from an area of high concentration to an area of low concentration

Osmosis Water moves across a membrane from an area of high concentration to an area of low concentration

Facilitated Diffusion Materials move through channels in the membrane

Active Transport DOES require energy (ATP) Moves from an area of low to high concentration

Photosynthesis Plants use sunlight to make energy (glucose)… 6CO 2 + 6H 2 O C 6 H 12 O 6 + 6O 2 12 H 2 O in 6 CO 2 in C 6 H 12 O 6 out 6 H 2 O out Chlorophyll Enzymes Radiant Energy In 6 O 2 out

Cellular Respiration C 6 H 12 O O 2  6CO 2 + H 2 O +{energy ATP} Glucose + Oxygen  Carbon Dioxide +Water + ATP

Reproduction

Why do cells divide? In eukaryotic cells –Repair Replace lost or damaged tissue –Growth Babies grow into adults –Sexual reproduction –Asexual reproduction Earthworms don’t have a sexual partner –Development Growing a fetus

Bacteria Reproduction Binary Fission –They copy DNA and split in half –Asexual reproduction

Eukaryote Reproduction

Chromosome DNA coiled up so that it can move easily during reproduction

Two Kinds of Eukaryotic Cells –Diploid Body cells Contain 46 chromosomes Reproduce by mitosis –Haploid Sex cells Contain 23 chromosomes Reproduce by meiosis

Two Kinds of Chromosomes –Autosomes Chromosome that do not determine gender Chromosomes on karyotype –Sex Chromosomes X and Y Female XX Male XY

The Cell Cycle Interphase: Cell grows, DNA copied Prophase: Nucleus disappears, DNA condenses, prepare to divide Metaphase: Chromosomes line up in middle Anaphase: Chromosomes separate Telophase: Nucleus reappears, chromosomes unravel Cytokinesis: Two daughter cells separate

Mitosis

Mitosis Swimming Pool