Biology Workbook For Dummies
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Biology is the study of life, from tiny bacteria to giant redwood trees to human beings. Understanding biology begins with knowing some of the basics, such as eukaryotic cell structure and common Latin and Greek roots that will help you decipher the sometimes-tough vocabulary.

Biology basics: Important components of eukaryotic cells

For biology students, knowing the components of eukaryotic cells and how they work is fundamental to understanding how organisms function. This table provides an overview of the most important eukaryotic cell structures and functions and how to recognize them.

Structure Function How to Recognize
Cell wall Rigid boundary around some cells Outermost boundary in plant, algal, fungal, and bacterial
cells. Cells with a cell wall are usually very regular in shape,
like they’ve been cut with a cookie cutter.
Chloroplasts Make food, transferring energy from sun to food molecules Organelles with two membranes and internal stacks of membranes
called grana, which look like layers of stripes.
Cytoskeleton Reinforces cell structures; helps move materials around
Looks like cables running through the cell.
Endoplasmic reticulum (ER) Rough ER has ribosomes, makes proteins; smooth ER makes
Folded sheets of membrane that ripple off of the nucleus of
cells. The rough ER has ribosomes stuck to it, so has a speckled
appearance. Smooth ER may look tubular, like coral, and has an
unspeckled surface.
Golgi Receives molecules from ER and modifies, tags, and ships them
Looks like a stack of pancakes surrounded by little membrane
Lysosomes Break down worn-out cell parts Small spheres within the cell; may contain partially broken
down materials.
Mitochondria Transfer energy from food to useful form for cells (ATP) Organelles with two membranes. The inner membrane is crinkled
into folds called cristae.
Nucleus Houses the genetic material Largest organelle, surrounded by a double membrane that has
little holes in it. May contain dark spots called
Plasma membrane Selective boundary of cell Outermost boundary in animal cells. Cells that have only a
plasma membrane for their boundary may be variable in shape.
Ribosomes Where proteins are made Look like tiny dots in the cell. May be loose in the cytoplasm
or attached to the rough endoplasmic reticulum.

Common Latin and Greek roots in biology vocabulary

Students in introductory biology classes typically have to learn more new vocabulary words than students taking a foreign language! The good news is that many science vocabulary words use the same Greek and Latin roots. When you know these roots, you can figure out what a word means, even if you’ve never heard it before.

This table shows you many roots to help you decipher words you hear in biology class.

Greek or Latin Root Meaning Examples
A-, An- Not, absent Abiotic: without life
Anoxygenic: without oxygen
Ab-, Abs- Away from Abscission: separation of leaves from tree
Allo- Another Allosteric: another binding site
Aqua- Water Aqueous: watery
Bi- Two Bilayer: double layered
Bio- Life Biology: the study of life
-cide Kill Bacteriocidal: kills bacteria
Cyt Cell Cytoplasm: the fluid inside a cell
Di- Two Disaccharide: a carbohydrate made of two simple sugars
Dis- Apart Disjoin: separate
Endo- Inside Endocytosis: a process that brings things into a cell
Epi- Upon, over Epidermis: the uppermost layer of tissue covering an
Eu- True Eukaryotes have a true nucleus
Ex- Out Exocytosis: a process that puts things out of cells
Geno- Give birth, beget Genetics: the study of heredity
Hetero- Mixed, unlike Heterozygous: a cell that has two different versions of a
Homo- Same Homozygous: a cell that has two identical versions of a
Hyper- Above Hypertonic: has a greater concentration of solutes
Hypo- Below Hypotonic: has a lower concentration of solutes
Inter- Between Interphase: the cellular phase between cell divisions
Iso- Same Isotonic: has same concentration of solutes
Locus Place A locus on a chromosome is the place where a gene is
Macro- Big Macrophage: a large phagocyte
-meter Measure Centimeter: a measurement that’s 1/100 of a meter
Micro- Small Microbiology: the study of living things too small to see with
the naked eye
Mono- One Monosaccharide: a single simple sugar
Olig- Few Oligosaccharide: a short chain of sugars
Ped-, Pod Foot Pseudopod: a “false foot” or projection of an amoeba
Phago- Eat Phagocytosis: a process where a white blood cell engulfs and
destroys bacteria and viruses
-phil Love Hydrophilic: mixes well with water
-phobia Fear Hydrophobic: doesn’t mix with water
Poly- Many Polypeptide: a chain of many amino acids
Pro- Before Prokaryotes: cells that evolved before nucleated cells
Stom- Mouth Stomates: openings in the surfaces of leaves
Zoo- Animal Zoology: the study of animals
Zygo- Join Zygote: a cell formed from the joining of sperm and egg

Organ systems in animals

Animal bodies range in organization from the loose collections of cells of sponges, to animals that have some organ systems like flatworms, to complicated vertebrates that have many organ systems.

Organ systems function by the coordinated effort of organs, which are composed of specialized groups of cells called tissues. This table shows the various organ systems and their functions.

Organ System Organs Function
Integumentary Skin, hair, nails, glands Protection, thermoregulation
Muscular Muscle fibers Movement
Skeletal Bones, cartilage Movement and support
Nervous Brain, spinal cord, nerves Signaling and regulation


Endocrine Glands Signaling and regulation
Circulatory Heart and blood vessels Movement of food, respiratory gases, and wastes
Respiratory Lungs and respiratory tract Gas exchange
Digestive Mouth, esophagus, stomach, intestine, liver, pancreas, gallbladder Breakdown of food molecules
Excretory Kidney, ureter, bladder, urethra Release wastes, regulate blood volume and composition
Immune Bone marrow, thymus, and lymphoid organs Defense against pathogens
Reproductive Gonads, genitals, glands and ducts Produce gametes (sperm and egg)

The parts and types of plants

Like animals, plants are made of cells and tissues, and those tissues form organs, such as leaves and flowers, that are specialized for different functions. Two basic organ systems exist in plants:

  • The shoot system, located above ground, helps plants capture energy from the sun for photosynthesis. Organs found within the shoot system include leaves, stems, cones, and flowers.
  • The root system, located below ground, absorbs water and minerals from the soil. Roots make up the root system.

The structure of each type of plant organ is tailored to match its function:

  • Leaves capture light and exchange gases with the atmosphere while minimizing water loss.
    • Many leaves are flattened, so they have maximum surface area for light capture.
    • Tiny holes called stomata in the surfaces of leaves open and close to allow plants to absorb carbon dioxide from the atmosphere and release oxygen.
    • Guard cells surround the stomata, ready to close them if water loss from the leaves becomes too great. The surface layer, or epidermis, of a leaf often has a coating of wax to further prevent water loss.
  • Stems support leaves and reproductive structures and also transport sugars and water throughout the plant.
    • Stems contain special types of tissues that give them strength. Woody plants have especially strong stems because they undergo secondary growth to thicken their stems and add layers of strong tissues.
    • Stems contain tissues that specialize in transport. Xylem transports water from a plant’s roots up to the leaves. Phloem transports sugars from the leaves throughout the plant. Young stems contain little packages of xylem and phloem, called vascular bundles.
  • Roots grow through the soil, anchoring the plant and absorbing water and minerals.
    • A root cap made of protective cells covers the tips of roots to prevent damage as they grow through the soil.
    • The root’s surface layer — also called an epidermis — contains cells that grow out into the soil, forming thin extensions called root hairs. These root hairs increase the root surface area so that the roots have more contact with the soil, which helps improve the absorption of water and minerals.
    • Roots contain a core of vascular tissue that carries water away from the roots and toward the shoots and brings sugars from the shoots toward the roots. Some roots, like those of a carrot, specialize in storing extra sugars for later use by the plant.

Reproductive parts

In some plants, specialized reproductive structures like flowers and cones produce the egg and sperm and may create protective structures around the young embryo. Flower structure also helps with pollination, the distribution of pollen (which contains sperm) to the plant’s female parts.

Stamens are the male parts of flowers. They consist of the anther, which makes pollen, and a thin stalk called a filament. Scientists call the ring of male parts within the flower the androecium (which literally means “man house”).

The flower’s female parts are the carpels, which may be joined together to form a pistil. The stigma is the part of the carpel that catches pollen, and the ovary is the swollen base that contains eggs in ovules. Many flowers have an elongated tube between the stigma and ovary that is called the style. Scientists call the ring of female parts within the flower the gynoecium (“woman house”).

The pretty parts of flowers are often showy petals, which help attract animals to flowers so they can help distribute pollen. Scientists call the ring of petals in the flower the corolla.

Flowers may also have a ring of green, leaf-like structures called sepals. Sepals help protect the flower when it’s still in the bud. In some flowers, the sepals look just like the petals and help attract pollinators. Scientists call the ring of sepals in the flower the calyx.

After fertilization of the eggs by sperm, the ovules within a flower become seeds, and the ovary becomes a fruit. Seeds protect the embryo, and fruits help scatter the seeds away from the parent plant.

A stalk called the peduncle supports the flower, which may also have a swollen base called the receptacle.

Based on the types of tissues they have and the reproductive structures they make, plants can be organized into four major groups:

  • Bryophytes are plants, such as mosses, that don’t have a vascular system and don’t produce flowers or seeds. Bryophytes also don’t have a true root system. Instead, many rely upon delicate anchoring structures called rhizoids.
  • Ferns and related plants have vascular tissue, but they don’t produce seeds.
  • Gymnosperms (also known as conifers) have vascular tissue and produce cones and seeds, but they don’t produce flowers.
  • Angiosperms (or flowering plants) have vascular tissue and produce both flowers and seeds. Scientists divide the most familiar flowering plants into two groups based on the number of cotyledons they contain in their seeds:
    • Monocots, like corn and lilies, have seeds that contain one cotyledon.
    • Dicots — beans, oak trees, and daisies — have seeds that contain two cotyledons.

Cotyledons, sometimes called seed leaves, supply nutrition to the embryo and then emerge as the first leaves begin to grow.

Differences between monocots and dicots

In addition to their difference in seed structure, monocots and dicots have distinct patterns in their structures and the way they grow.

This table presents several of the key structural differences between monocots and dicots.

Feature Monocots Dicots
Cotyledons in seeds One Two
Bundles of vascular tissue in stem Scattered throughout Form definite ring pattern
Root system Fibrous Taproot
Leaf veins Run parallel Form a net pattern
Flower parts Are in threes and multiples of threes Are in fours and fives and multiples of fours and fives

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