Cell Biology Flashcards

Flashcards for Cell Biology Exam Review

What is the fundamental structural and functional unit of all living beings?

The cell

What is the smallest part of an organism capable of independent existence?

A cell

Who constructed the first microscope?

Antony van Leeuwenhoek

What type of lens did Leeuwenhoek's microscopes use?

Single biconvex lens

What is the magnification power of some of Leeuwenhoek's microscopes?

Up to 200 times

Who developed a microscope using two lenses?

Robert Hooke

What are microscopes using two lenses known as?

Compound microscopes

What did Hooke examine under his microscope?

A thin slice of cork

What did Hooke compare the structure of cork to?

Rooms, or cells, of monks in a monastery

What does an electron microscope use to magnify images?

Beams of electrons

What is the magnification capability of an electron microscope?

Over 200,000 times

In what year did Schleiden announce that every plant is made up of a large number of cells?

1838

Who declared that all animals and plants are composed of cells?

Theodor Schwann

What year was the Cell Theory proposed?

1839

Who added to the cell theory that all cells arise from pre-existing cells?

Rudolf Virchow

What are the three major points of the Cell Theory?

1. The cell is the smallest unit of structure. 2. The cell is the unit of function. 3. All cells arise from pre-existing cells.

What is the relationship between an organism's size and the number of cells in its body?

Larger organisms have a greater number of cells.

Name three examples of single-celled organisms.

Bacteria, yeast, amoeba

Name two examples of few-celled organisms.

Spirogyra, Volvox

Give two examples of multi-celled organisms.

Human beings, Mango

What is the estimated number of cells in an average-sized adult human?

1000 million million cells

What are the estimated number of nerve cells in the human brain cortex?

10,000 million

What are the ranges of the size of bacteria cells?

0.3-5.0 micrometre

What is an example of the longest cells in the body?

Nerve cells

What is the largest single cell of the living world today?

Ostrich egg

What are the two main reasons cells remain small in size?

Rapid communication and large surface area / volume ratio

What is the benefit of a large surface area/volume ratio in cells?

Greater diffusion of substances in and out of the cell

Name three categories of substances that are ensured greater diffusion due to large surface/volume ratio within cells.

Nutrients, metabolic wastes, respiratory gases

What are the three essential parts of a generalized cell?

Cell membrane, nucleus, and cytoplasm

What are cell organelles?

Parts of a cell with a definite shape, structure, and function

What is the function of the cell membrane?

Surrounds each cell

What is the permeability of the cell membrane?

Selective

What is the main component of the cell wall?

Cellulose

What is the cytoplasm?

A semi-liquid substance occupying most of the cell

What is the endoplasmic reticulum (ER)?

Irregular network of double membranes distributed over the entire cytoplasm

What is the function of ribosomes?

Sites of protein synthesis

What is the function of mitochondria?

Release energy through cell respiration

What energy-rich compound is produced by mitochondria?

ATP (adenosine triphosphate)

What is the function of the Golgi apparatus?

Secretion of enzymes, hormones, etc.

What is the function of lysosomes?

Intracellular digestion

What is the function of the centrosome in animal cells?

Forms spindle fibers during cell division

What are plastids?

Organelles with different shapes in plant cells

Name three types of plastids

Leucoplasts, chromoplasts, and chloroplasts

What is the function of leucoplasts?

Store starch

What pigments are associated with chromoplasts?

Xanthophyll (yellow) and carotene (orange-red)

What is the function of chloroplasts?

Trap solar energy for photosynthesis

What is the main function of a nucleus?

Regulate and coordinate various life processes of the cell

What are chromatin fibers?

Threadlike structures in the nucleoplasm

What are the cells in which the nuclear membrane is absent called?

Prokaryotic cells

What are cells in which a double nuclear membrane is present called?

Eukaryotic cells