Cell Structure, Function, and Human Body Systems Overview

Cell Theory

Cells are the basic unit of life; all living things are made of cells; all cells come from pre-existing cells

Cell Metabolism

Processes cells use to obtain energy, build structures, eliminate waste, and reproduce

Organelle

Any number of organized or specialized structures within a living cell

Prokaryotic Cells

Simple cells without membrane-bound organelles (e.g., bacteria)

Eukaryotic Cells

Complex cells with membrane-bound organelles (e.g., plants and animals)

Cell Membrane

A semi-permeable membrane that controls movement into and out of the cell

Cytoplasm

Jelly-like fluid which holds all organelles and contains many of the materials involved in cell metabolism

Nucleus

Serves as the control center for cell metabolism and reproduction

Mitochondria

Contains enzymes that convert the stored energy into useable energy for cellular activity (cellular respiration)

Ribosomes

Produces proteins

Golgi Apparatus

Sorts and packages proteins, collects and secretes the products of the cell

Endoplasmic Reticulum (ER)

Serves as a pathway for the transport of materials throughout the cell; also associated with synthesis and storage

Vacuole

Fluid-filled organelles enclosed by a membrane; contains stored food or wastes

Cell Wall

Gives the cell it’s shape, provides protection and rigid yet porous to allow somethings in and out the cell

Chloroplast

Converts energy from the sun into stored energy for photosynthesis (CO2 + H2O + light → Glucose + O2)

Lysosome

Involved in the digestion of food within the cell

Plant Cells

Have cell wall, chloroplasts, large vacuole

Animal Cells

Have lysosomes and centrioles; no cell wall or chloroplasts

DNA (Deoxyribonucleic Acid)

Molecule that contains genetic instructions

Double Helix

In 1953, James Watson and Francis Crick created the double helix model of DNA

Nucleotide

Basic unit of DNA (sugar + phosphate + base)

Base Pairing Rules

A pairs with T, G pairs with C

Gene

Segment of DNA that codes for a protein

Chromosome

Condensed DNA structure in the nucleus

Protein

Molecule that performs functions like structure, enzymes, and transport

Cell Cycle

Process of cell growth and division

Interphase

Cell prepares for division (90% of cycle)

Mitosis

Division of the nucleus

Cytokinesis

Division of cytoplasm

Prophase

Chromosomes condense, nuclear membrane breaks down

Metaphase

Chromosomes line up in the middle

Anaphase

Chromatids pulled apart

Telophase

Nuclear membrane reforms

Result of Mitosis

Two identical daughter cells

Checkpoint

Control point ensuring cell is ready to divide

Apoptosis

Programmed cell death

Cancer

Uncontrolled cell division due to mutations

Tumor

Mass of abnormal cells

Benign Tumor

Non-spreading, slow-growing

Malignant Tumor

Spreads and grows rapidly

Carcinogen

Substance that causes DNA mutations (e.g., UV, smoking)

Stem Cell

Unspecialized cell that can become other cell types

Embryonic Stem Cells

Can become any cell (pluripotent)

Adult Stem Cells

Limited to certain cell types (multipotent)

Meristematic Cells

Plant stem cells for growth

Cell Differentiation

Process where cells become specialized

Factors Affecting Differentiation

Cytoplasm, environment, neighboring cells

Epithelial Tissue

Covers surfaces and lines organs

Connective Tissue

Supports and binds (bone, blood, fat)

Muscle Tissue

Contracts to create movement

Nervous Tissue

Sends signals through the body

Dermal Tissue

Outer protection layer of plants

Ground Tissue

Photosynthesis and support in plants

Vascular Tissue

Transports water and nutrients in plants

Xylem

Transports water

Phloem

Transports sugars

Cell

Basic unit of life

Tissue

Group of similar cells

Organ

Group of tissues working together

Organ System

Group of organs working together

Digestive System

Breaks down food and absorbs nutrients

Respiratory System

Exchanges oxygen and carbon dioxide

Circulatory System

Transports oxygen, nutrients, and waste

Excretory System

Removes liquid waste

Immune System

Defends against disease

X-ray

Uses radiation to view bones

CT Scan

3D image using multiple X-rays

Ultrasound

Uses sound waves for real-time imaging

MRI

Uses magnets and radio waves for detailed images

Endoscopy

Camera inserted into body to view internal organs