Science Exam Review: Biology

Prokaryotes

Bacteria without a nucleus.

Eukaryotes

All other organisms such as animals, plants, fungi, and algae.

Organelles

Cell structures that perform a specific function for the cell.

Asexual Reproduction

The process of producing offspring from only one parent; offspring are genetically identical to the parent.

Sexual Reproduction

The process of producing offspring by the fusion of two gametes; offspring have genetic information from each parent.

Concentration

The amount of a substance (solute) present in a given volume of a solution.

Diffusion

Transportation mechanism for moving chemicals into and out of the cell, from an area of higher concentration to an area of lower concentration.

Osmosis

The movement of a fluid, usually water, across a membrane toward an area of high solute concentration.

Cell Cycle

The three stages (interphase, mitosis, and cytokinesis) through which a cell passes as it grows and divides.

Interphase

The phase of the cell cycle during which the cell performs its normal functions and its genetic material is copied in preparation for cell division.

Prophase

The first stage of mitosis, in which the chromosomes become visible and the nuclear membrane dissolves.

Metaphase

The second stage of mitosis, in which the chromosomes line up in the middle of the cell.

Anaphase

The third phase of mitosis, in which the centromere splits and sister chromatids separate into daughter chromosomes and move toward opposite ends of the cell.

Telophase

The final phase of mitosis, in which the chromatids unwind and a nuclear membrane reforms around the chromosomes at each end of the cell.

Cytokinesis

The splitting or division of the cytoplasm or the entire cell.

Cancer

A broad group of diseases that result in uncontrolled cell division.

Tumour

A mass of cells that continue to grow and divide without any obvious function in the body.

Benign Tumour

A tumour that does not affect surrounding tissues other than by physically crowding them.

Malignant Tumour

A tumour that interferes with the functioning of surrounding cells; a cancerous tumour.

Mutation

A random change in DNA.

Carcinogen

Any environmental factor that causes cancer.

Heredity

DNA passed from one generation to another.

Metastasis

The process of cancer cells breaking away from the original tumour and establishing another tumour elsewhere in the body.

Specialized Cell

A cell that can perform a specific function.

Hierarchy

An organizational structure with more complex or important things at the top and simpler or less important things below it.

Tissue

A collection of similar cells that perform a particular but limited function.

Organ

A structure composed of different tissues working together to perform a complex body function.

Organ System

A system of one or more organs and structures that work together to perform a major vital body function such as digestion or reproduction.

Epithelial Tissue

A thin sheet of tightly packed cells that covers body surfaces and lines internal organs and body cavities.

Connective Tissue

A specialized tissue that provides support and protection for various parts of the body.

Muscle Tissue

A group of specialized tissues containing proteins that can contract and enable the body to move.

Nerve Tissue

Specialized tissue that conducts electrical signals from one part of the body to another.

Digestive System

The organ system made up of the mouth, esophagus, stomach, intestines, liver, pancreas, and gall bladder; it takes in, breaks up, and digests food, then excretes waste.

Esophagus

A muscular tube connecting the mouth to the stomach.

Liver

A large organ attached to the intestine close to the stomach.

Pancreas

A leaf-shaped organ found under the stomach.

Gall Bladder

A pear-shaped muscular organ located in the upper right abdomen.

Cell Theory

States that all living things are made of one or more cells and their products; the cell is the simplest unit of life; and all cells come from other cells.

Prokaryotes

Bacteria without a nucleus.

Example of a Prokaryote

E. coli.

Eukaryotes

All other organisms such as animals, plants, fungi, and algae.

Single-celled Organism

An organism made of only one cell.

Example of a Single-celled Organism

Amoeba.

Multicellular Organism

An organism made of many cells.

Example of a Multicellular Organism

Fungi.

Organelles

Cell structures that perform a specific function for the cell.

Cytoplasm

Jelly-like material that stores substances, allows chemical reactions, and allows organelles to move around.

Cell Membrane

Semi-permeable, flexible, double-layered structure that supports the cell and controls what enters and leaves.

Nucleus

Contains genetic information that controls cell activities and protects DNA.

Mitochondria

The powerhouse of the cell; makes energy available to the cell.

Endoplasmic Reticulum

A network of tubes and pockets that transports materials through the cell.

Golgi Bodies

Collect and process materials and help produce mucus.

Small Vacuoles

Store substances, remove wastes, and maintain internal fluid pressure.

Ribosomes

Produce proteins.

Cell Wall

Rigid, porous structure made of cellulose that supports and protects plant cells.

Large Central Vacuole

Large water-filled sac that stores water and keeps plant cells firm.

Chloroplast

Green organelle containing chlorophyll; site of photosynthesis.

Organelles Found in Both Plant and Animal Cells

Nucleus, vacuoles, cell membrane, endoplasmic reticulum, Golgi apparatus, ribosomes, mitochondria, and cytoplasm.

Mitosis

Process that allows growth, repair, replacement, and asexual reproduction.

Asexual Reproduction

Producing offspring from one parent; offspring are genetically identical to the parent.

Sexual Reproduction

Producing offspring through fusion of two gametes; offspring inherit DNA from both parents.

Asexual Reproduction Characteristics

One parent, genetically identical offspring, simple and fast.

Sexual Reproduction Characteristics

Two gametes involved, genetically varied offspring, longer and more complex.

Why Cells Divide Instead of Growing Larger

Materials such as nutrients and wastes cannot move efficiently through very large cells.

Concentration

The amount of solute present in a given volume of solution.

Diffusion

Movement of substances from an area of higher concentration to lower concentration.

Osmosis

Movement of water across a membrane toward an area of higher solute concentration.

Importance of Diffusion and Osmosis

Allow nutrient uptake, waste removal, and maintenance of cell balance.

Cell Cycle

The stages through which a cell grows and divides: interphase, mitosis, and cytokinesis.

Interphase

Phase during which the cell performs normal functions and copies its DNA.

G1 Phase

Cell growth and normal metabolic activities.

S Phase

DNA is replicated.

G2 Phase

Cell checks DNA replication and prepares organelles for division.

Mitosis

Division of the nucleus into two identical nuclei.

Prophase

Chromosomes become visible and the nuclear membrane dissolves.

Metaphase

Chromosomes line up in the middle of the cell.

Anaphase

Centromeres split and sister chromatids move to opposite poles.

Telophase

Chromatids unwind and new nuclear membranes form.

Cytokinesis

Division of the cytoplasm to form two daughter cells.

Result of Mitosis

Two genetically identical daughter cells.

Importance of Mitosis

Allows growth, repair, replacement of damaged cells, and maintains identical DNA.

Number of Chromosomes in Human Diploid Cells After Mitosis

46 chromosomes.

Cell Cycle Checkpoints

Ensure DNA is undamaged, replicated correctly, nutrients are available, and signals permit division.

Cancer

A broad group of diseases resulting in uncontrolled cell division.

Tumour

A mass of cells that continues to grow and divide without a useful function.

Benign Tumour

A tumour that crowds nearby tissues but does not invade them.

Malignant Tumour

A cancerous tumour that interferes with surrounding tissues.

Mutation

A random change in DNA.

Carcinogen

An environmental factor that causes cancer.

Examples of Carcinogens

Tobacco, radiation, HPV, Hepatitis B, and microplastics.

Heredity

Passing DNA from one generation to the next.

Metastasis

The spread of cancer cells from the original tumour to other parts of the body.

Cancer Screening

Checking for cancer before symptoms appear.

Importance of Cancer Screening

Increases the chances of finding cancer early.

Pap Test

A screening test for cervical cancer.

Breast Self-Examination

Check for lumps that may indicate breast cancer.

Testicular Self-Examination

Check for signs of testicular cancer.

Blood Test for Colon Cancer

Used to screen for colon cancer.

Cancer Diagnosis Methods

Endoscopy, X-rays, ultrasound, biopsy, and MRI.

Goal of Cancer Treatment

Slow tumour growth or destroy cancer cells.