1st Semester Exam Review

1st Semester Exam Review

7th Grade Science

Levels of Organization

Non- living

Atoms

Molecules

Organelles

Living

Cells

Tissues

Organs

Organ Systems

Organisms

Non Living

Atoms

An atom tiny particles that make up all living and non-living matter

Examples:

oxygen, nitrogen, gold

Molecules

when two or more atoms combine to form a new substance

Examples:

water H2O

carbon dioxide CO2

glucose C6H12O6

oxygen O2

Organelles

tiny organs or cell parts with specific jobs

Examples:

mitochondria, nucleus, Golgi apparatus

LIVING

LEVEL 1 - Cells

Are the basic unit of structure and function in living things.

May serve a specific function within the organism

Examples- blood cells, nerve cells, bone cells, etc.

LEVEL 2 - Tissues

A group of similar cells that perform a common funcion

Examples - blood, nervous, bone, etc.

Humans have 4 basic tissues:

connective, epithelial, muscle, and nerve.

LEVEL 3 Organs

Made up of tissues that work together to perform a specific function

Examples - heart, brain, skin, etc.

LEVEL4 - Organ Systems

Groups of two or more organs that work together to perform a specific function for the organism.

Examples - circulatory system, nervous system, skeletal system, etc.

LEVEL 5 - Organisms Characteristics of living things

Entire living things that can carry out all basic life processes. Meaning they can take in materials, release energy from food, release wastes, grow, respond to the environment, and reproduce.

Usually made up of organ systems, but an organism may be made up of only one cell such as bacteria or protist.

Examples - bacteria, amoeba, mushroom, sunflower, human

Human Body Organ Systems

The Human body has 11 organ systems - circulatory, digestive, endocrine, excretory (urinary), immune(lymphatic), integumentary, muscular, nervous, reproductive, respiratory, and skeletal.

Lets review what we know about them!

Circulatory System

Function

Carries oxygen and food to cells

Carries carbon dioxide away from cellsOrgans

Organs/Structure

Heart

Blood

Blood vessels

Digestive System

Function

Breaks down food into smaller particles

Used by the bodys cells for energy

Organs/Structures

Mouth

Esophagus

Stomach

Intestines

Endocrine System

Function

Controls:

Growth

Development

Metabolism

Reproduction

Organs/Structures

hypothalamus

pituitary gland

thyroid

parathyroids

adrenal glands

pineal body

reproductive glands

Excretory (urinary) System

Function

Removes waste from the body

Organs/Structures

Skin

Lungs

Kidney

bladder

Immune (lymphatic) System

Function

Protects the body from disease

Organs/Structures

White blood cells

Spleen

Lymph nodes

Integumentary System

Function

Organs and structures that cover and protect the body

Acts as a barrier against infection and injury

Organs/Structures

Skin

Hair

Nails

Sweat and Oil Glands

Muscular System

Function

Works with skeletal system to produce movement

Organs/Structures

Skeletal muscles

Smooth muscles

Heart muscles

Nervous System

Function

Organizes the body's response to stimuli

Sends electrical signals throughout the body

Organs/Structures

Brain

Spinal cord

Sense organs

Reproductive System

Function

Produces reproductive cells

Responsible for producing offspring

Respiratory System

Function

Provides oxygen to the bodys cells for cellular respiration

Organs/Structures

Mouth

Nose

Trachea

Bronchi

lungs

Skeletal System

Function

Supports the body and protects internal organs

Organs/Structures

Bones

Cartilage

Ligaments

Tendons

Cell Structure & Function

http://koning.ecsu.ctstateu.edu/cell/cell.html

Cell Theory

All living things are made up of cells.

Cells are the smallest unit of all living things.

All cells come from preexisting cells.

Definition of Cell

A cell is the smallest unit that is capable of performing life functions.

Examples of Cells

Amoeba Proteus

Plant Stem

Red Blood Cell

Nerve Cell

Bacteria

Two Types of Cells

Prokaryotic

Eukaryotic

Prokaryotic

Do not have structures surrounded by membranes

Few internal structures

One-celled organisms, Bacteria

http://library.thinkquest.org/C004535/prokaryotic_cells.html

Eukaryotic

Contain organelles surrounded by membranes

Most living organisms

Plant

Animal

http://library.thinkquest.org/C004535/eukaryotic_cells.html

The Advantages to being Multicellular:

Grow bigger

Specialized Cells

Live Longer

Typical Animal Cell

http://web.jjay.cuny.edu/~acarpi/NSC/images/cell.gif

http://waynesword.palomar.edu/images/plant3.gif

Typical Plant Cell

Cell Parts

Organelles

Cell Membrane

Outer membrane of cell that controls movement in and out of the cell

Double layer

http://library.thinkquest.org/12413/structures.html

Cell Wall

Most commonly found in plant cells & bacteria

Supports & protects cells

http://library.thinkquest.org/12413/structures.html

Inside the Cell

Nucleus

Directs cell activities

Separated from cytoplasm by nuclear membrane

Contains genetic material - DNA

Nuclear Membrane

Surrounds nucleus

Made of two layers

Openings allow material to enter and leave nucleus

http://library.thinkquest.org/12413/structures.html

Chromosomes

In nucleus

Made of DNA

Contain instructions for traits & characteristics

http://library.thinkquest.org/12413/structures.html

Nucleolus

Inside nucleus

Contains RNA to build proteins

http://library.thinkquest.org/12413/structures.html

Cytoplasm

Gel-like mixture

Surrounded by cell membrane

Contains hereditary material

Endoplasmic Reticulum

Moves materials around in cell

Smooth type: lacks ribosomes

Rough type (pictured): ribosomes embedded in surface

http://library.thinkquest.org/12413/structures.html

Ribosomes

Each cell contains thousands

Make proteins

Found on ribosomes & floating throughout the cell

http://library.thinkquest.org/12413/structures.html

Mitochondria

Produces energy through chemical reactions breaking down fats & carbohydrates

Controls level of water and other materials in cell

Recycles and decomposes proteins, fats, and carbohydrates

http://library.thinkquest.org/12413/structures.html

Golgi Bodies

Protein 'packaging plant'

Move materials within the cell

Move materials out of the cell

http://library.thinkquest.org/12413/structures.html

Lysosome

Digestive 'plant' for proteins, fats, and carbohydrates

Transports undigested material to cell membrane for removal

Cell breaks down if lysosome explodes

http://library.thinkquest.org/12413/structures.html

Vacuoles

Membrane-bound sacs for storage, digestion, and waste removal

Contains water solution

Help plants maintain shape

http://library.thinkquest.org/12413/structures.html

Chloroplast

Usually found in plant cells

Contains green chlorophyll

Where photosynthesis takes place

http://library.thinkquest.org/12413/structures.html

The Cell Cycle

Interphase

a period of growing and preparing for cell division

-G1 phase cell takes in nutrients and grows to its full size

-S phase makes a copy of chromosomes (genetic material)

-G2 phase - produces extra organelles and cytoplasm

M-Phase

the process of cell division: mitosis

Prophase

chromosomes condense into rod like structures

nuclear membrane breaks apart

centrioles move to opposite sides

fibers from and attach to centromeres

Metaphase

chromosomes line up along the middle of the cell

Anaphase

the two chromatids are pulled apart by the spindle fibers and begin to move to opposite ends of the cell

Telophase

chromosomes go back to looking like threads (chromatin).

Nuclear membrane forms around the chromatin; the nucleolus reappears

CYTOKINESIS

division of cytoplasm into two cells.

In plant cells a cell plate forms in between the two nuclei.

The cell plate eventually divides the two cells & forms the cell wall.

Binary Fision

Cell Cycle of Unicellular Organisms

Diffusion

The movement of molecules from a region of higher concentration to a region of lower concen