Cellular Processes

How is the body organized from highest to lowest level

• Organism

• 11 Systems

• 60+ Organs

• 4 Types of tissues

• Trillions of cells

What is Homeostasis

Helps the body maintain a stable internal environment; self-regulate to maintain stable

What are the 4 Tissue Types?

• Muscular

• Connective

• Nervous

• Epithelial

Cellular Organization

• Nucleus

• Endoplasmic Reticulum

• Mitochondria

• Golgi apparatus

• Lysosomes

• Centrioles

• Vacuoles

Genetic Information and DNA Structure

• Each human somatic cell contains 46 chromosomes

  • arranged in 23 pairs

• They are contained within nucleus for protection

What are the characteristics of DNA?

• Double-helix shaped

• The sides of the ladders are made of sugar and phosphate molecules

• Rungs are made of nitrogen bases (adenine, thymine, cytosine, & guanine)

  • Base pairing: A - T; G - C

Protein Synthesis and Gene Expression

• Transcription: the gene’s DNA sequence is copied into mRNA in the nucleus

• Translation: ribosomes read the mRNA code and assemble amino acids into a polypeptide chain (makes protein)

  • U (uracil) is made rather than a T

Cell Division

Cells divide for growth, development, tissue repair, and reproduction

The Cell Cycle

Consists of interphase, during which the cell grows and replicates DNA, and the mitotic phase during division occurs

What happens during mitosis?

• Period of division in somatic (body) Cells

• Division of chromosomes and then cytoplasm

• One parent cell makes two identical daughter cells

  • Maintaining chromosome number

What happens during meiosis?

• Period of division in sex cells (gametes)

• One parent cell makes four different daughter cells

  • Produces half the chromosome number

  • Introduces genetic variation (critical for evolution & reproduction)

Cell Membrane Structure

Composed of a phospholipid bilayer with embedded proteins (Polar heads and non-polar tails)

What is passive transport?

• Relies on concentration gradients and includes diffusion, facilitated diffusion, and osmosis

• Molecules move from high to low concentration

  • Does NOT require energy

What is Osmosis

• Movement of solvent molecules (water) across a semipermeable membrane

• Molecules move from low to high concentration

  • Does NOT require energy

What is a facilitated diffusion

• Larger molecules need to be assisted (facilitated) across the membrane by channels made of protein

What is active transport?

Requires energy to move substances against gradients

What is Vesicular transport?

• allows bulk movement of materials

• endocytosis: into cell

• exocytosis: out of cell