Chapter 3 Cells and Their Functions

Objectives List 3 types of microscopes Describe the function and composition of the plasma membrane Describe the cytoplasm and the organelles Describe the composition, location, and function of DNA Compare the 3 functions of RNA Explain briefly how cells make proteins Name and briefly describe mitosis Define 8 methods by which substances enter and leave the cell Explain what happens if cells are placed in solutions with the same concentration as the cell fluid and different as the cell fluid Define cancer List several risk factors for cancer

Basic unit of all life. The study of cells is cytology.

Microscopes 3 types: Compound, Transmission, and Scanning Electron

Cell Structure Plasma Membrane

Cell Structure Nucleus

Cell Structure Cytoplasm

Cell Structure Organelles

Protein Synthesis DNARNA Carries genetic message Located in nucleus Composed of nucleotides Double-stranded Located in cytoplasm Translates DNA message 3 types (messenger, ribosomal and transfer) Single-stranded

Cell Division Serves for growth, repair, and reproduction Meiosis : Chromosome number divided in half (forms the sex cells) Mitosis : Cell division that results in 2 identical daughter cells (exactly like parent cell)

Meiosis First, cuts the chromosome number in half to prepare for the union of the sperm and egg You need the reduction in chromosome number to have offspring with the right number.

Mitosis Continuous process, but distinct stages can be identified: - Prophase: nuclear membrane disappears, centrioles move toward opposite ends - Metaphase: chromosomes line up across center - Anaphase: centromere separates and duplicated chromosomes move toward opposite ends of cell - Telophase: membranes develops around each new group of separated chromosomes, forming two new nuclei

Movement of Substances across the Plasma Membrane Some substances can enter the cell, others can not. The plasma membrane serves as a barrier between the cell and its environment. Separated into: movement that requires energy movement that does not require energy

Solutions you need to know….

Cancer is defined as a tumor that spreads to other tissues. Also known as a malignant neoplasm.

Risk Factors for Cancer Heredity Chemicals Ionizing Radiation Physical Irritation Diet Viruses

Your understanding of cell structure and function will help you to understand tissues, organs, systems and the whole human body! Understanding…