Biology Unit 1 Characteristics and organization of living organisms

Characteristics of Living Organisms

Organisms reproduce, need energy, grow and develop, respond to stimuli, evolve from other organisms, and are made up of cells.

Cell Theory

1. All living things are made up of cells.

2. 2. All cells perform life processes.

3. 3. All cells come from other cells.

Prokaryotic Cells vs. Eukaryotic Cells

Prokaryotic cells are small, simple, lack a nucleus, and are mostly unicellular;

eukaryotic cells are larger, complex, have a nucleus, and are mostly multicellular.

Functions of Nucleus

Contains genetic material and controls cell activities in both plants and animals.

Functions of Cytoplasm

Where most chemical processes take place, controlled by enzymes in both plants and animals.

Function of Cell Membrane

Controls the movement of substances in and out of the cell in both plant and animal cells.

Function of Ribosomes

Site of protein synthesis, found in both plant and animal cells.

Function of Cell Wall

Strengthens the cell, present only in plant cells.

Function of Chloroplasts

Contains chlorophyll; absorbs light energy for photosynthesis, found only in plant cells.

Function of Permanent Vacuole

Filled with cell sap to keep the plant turgid, present only in plant cells.

Examples of Cell Specialization

Nerve cells carry messages, root hair cells absorb water and minerals, red blood cells transport oxygen, sperm cells deliver male DNA.

Tissue Definition

A group of the same cells working together.

Organ Definition

A complex structure made up of different tissues that performs specific functions.

Organ System Definition

A group of organs working together to perform major functions, such as the circulatory or digestive system.

Typical Cell Size

Typical cells are measured in micrometers; conversion between micrometers and other units is required.

Light Microscope Components

Includes eyepiece, objective, stage, focus, condenser, diaphragm, and coverslip.

Stained Slides Preparation

Making stained slides involves applying a stain to enhance visibility under a microscope.

Calculating Actual Cell Size

Actual size of cells can be determined if the magnification of a drawing or a scale line is given.

Electron Microscopes

Electron microscopes reveal the presence of organelles such as mitochondria and ribosomes.