Unit l - Introduction to Cell Flashcards by Haru Haru

What is cell?

 small, membrane-enclosed units  Filled with aqueous solution of chemicals
 Ability to multiply or divide
 Fundamental unit of life

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Diversity of cells

 Cells vary enormously in appearance and function.
Size – Lactobacillus vs. Frog’s egg
Chemical reactions
Cellular activities

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Similarity of cells

 Cells have similar basic chemistry.  Cells have genes, genetic instruction.
 Genes are stored in the DNA.
 genetic information flows:

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Flow of genetic information

 from DNA to RNA (transcription);  and from RNA to protein (translation).

Replication - Transcription - Translation

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Process of DNA making a copy of itself

Replication

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Process of copying DNA into mRNA

Transcription

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Process of protein synthesis from mRNA sequence

Translation

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 Discovered cells while looking at a thin slice of cork.
 Cells as tiny boxes or a honeycomb.
 He thought that cells only existed in plants and fungi

Robert Hooke
1665

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Pond scum was called ______

Animalcules

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150-200 year gap, very few cell theory advancements were made because of ________

Spontaneous Generation

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Example of Spontaneous Generation

Mice from dirty clothes/corn husks Maggots from rotting meat

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used a handmade microscope to observe pond scum (single-celled organisms)
 Pond scum was called “ animalcules”
Observed blood cells from fish,birds, frogs, dogs, and humans. Cells are found both in animals and plants.

1673
Anton Van Leeuwenhoek

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 ________ (_____), discovery of nucleus.
 An opaque spot in cells of epidermis of orchids.
 Then observed other cells.
 ________ -random motion of particles.
Noticed that pollen grains in water jiggled called _______

Robert Brown (1831)
Brownian motion

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______________ (_____) Coined the term “protoplasm” to describe the contents of the cell
Nucleus in bird’s egg, sweat galnds in the skin, nerve cells, muscle fiber.
Used on fingerprints
Describe the movement cilia
Use of microtome

Johannes Purkinje, Czech (1839)

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Spontaneous Generation disproved by __________ during ________

Louis Pasteur during 19th century advancement

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Very few cell theory advancement were made because of _________ with a year gap of _____-_____

Spontaneous Generation
150-200 year gap

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The term cell was delivered from latin word _____ meaning ______

Cella
A little room

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Robert Hooke explained his work in a book, namely, ______

Micrographia

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• He was the father of Microbiology
• He observed free living cells in pondwater

Anton Van Leeuwenhoek

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Johannes Purkinje, Czech coined the term ______

Protoplasm (the cytoplasm and nucleus)

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The cell theory was proposed by _______ and ______

Matthias Schleiden and Theodor Schwann

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_______ was first to observe cells have a thin outer layer which we now call as ________

Theodor Schwann
Plasma membrane

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It denotes that all plants and animals are consist of cells and that the cell is the basic unit of life

Cell theory

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The concept of cell arising from pre existing cell was started by virchow as _________

Omnis cellula e cellula

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He invented the electronmicroscope which enables to see the complex structure of the cell

Vladimir Zworykin

Cells have certain common structure, these are All cells have certain structures in common.

Genetic material Cytoplasm Plasma membrane

Characteristics of a cell

Cell Membrane Ribosomes Cytoplasm Cells contain DNA Found in the nucleus Cells are independent units of life

Two basic types of cells

Prokaryotic cells Eukaryotic cells

• Region of cytoplasm where prokaryote’s genome/ DNA is located. • Usually a singular, circular chromosome.

Nucleoid

• Small extra piece of chromosome/genetic material. • 5 - 100 genes

Plasmid

• Also known as proto-plasm. • Gel-like matrix of water, enzymes, nutrients, wastes, and gases and contains cell structures. • Location of growth, metabolism, and replication.

Cytoplasm

• Bacteria’s way of storing nutrients. • Staining of some granules aids in identification.

Granules

__________ is thought to be a feature only of eukaryotes. Discovery of ________ is a major advancement in the study of prokaryotes.

Cytoskeleton

Separates the cell from its environment. Phospholipid bilayer _________ - water fearing _________ - water loving Membrane is ___________

Plasma membrane Hydrophobic Hydrophilic Semi - permeable

Cell wall of prokaryotes

Gram positive - peptidoglycan cell wall Gram negative - lipopolysaccharide cell wall

Surface appendages

Flagella Axial filament Fimbriae Pili

Long, thin extensions

Flagella

Wind around bacteria, causing movement in waves

Axial filament

• short, fine appendages around the cell. • No role in motility

Fimbriae

Tubes that are longer than fimbriae but shorter than flagella.

Pili

Cell shapes of prokaryotic cell

1. Bacillus 2. Cocus 3. Spiral shaped (spirillum, spirochete) Coccobacilli Filamentous Vibrios Fusiform

1. Sherical shape 2. rod shape 3. Spiral shape a. Spiral with flexible cell wall, axial filament b. Spiral with rigid cell wall, flagella

1. Coccus 2. Bacillus 3. Spiral a. Spirochete b. Spirillum

• __________ = bacilli that occur in long threads • _________ = elongated coccal form • _________ = bacilli with tapered ends • ________ = short, slightly curved rods

1. Filamentous 2. Coccobacilli 3. Fusiform 4. Vibrios

Characteristics of prokaryotes

does not have a nucleus single celled organisms have few organelles perform few functions Eat Respire Reproduce smaller than other cells Bacteria are the only known prokaryotes

Characteristics of a virus

• are not made of cells • need a host cell to reproduce • A virus is very small compared to a cell. • Like cells, viruses contain nucleic acids

Characteristics of Eukaryotes

has a nucleus can be single or multicellular have many organelles, performing complex functions specialized to perform specific functions larger than prokaryotic cells Animals, plants, fungi and protists are made of eukaryotic cells

• Nickname: “The Control Center” • Function: holds the DNA

Nucleus

It consist of: Cytosol - liquid portion Organelles - specialized cellular compartments Inclusions - chemical substances Glycogen - (muscle and liver cells) Lipid droplets - (fat cells) Melanin granules - (skin and hair cells)

Cytoplasm

Nickname: “The Powerhouse” Function: Energy formation Breaks down food to make ATP ATP: is the major fuel for all cell activities that require energy

Mitochondria

• Function: makes proteins • Found in all cells, prokaryotic and eukaryotic

Ribosomes

It is composed of rRNA and protein

Ribosomes

__________ – synthesize proteins that function within the cell __________ – synthesize proteins incorporated into cell membranes

Free ribosomes Attached ribosomes

________ – network of rods that support the cell

Cytoskeleton

• ________ – thick rods composed of tubulin. Eg. centrioles • _________ – thin filaments composed of actin • _________ – tough protein fibers

Microtubules Microfilaments Intermediate filaments

• fingerlike projections of the plasma membrane; • increase surface area for absorption Example: ______

Microvilli ex: intestine

• short hair-like projections; propel substances over surface of cell Example: ________

Cilia ex: respiratory tract

long hair-like projections; propel the cell ex: _____

Flagella Sperm cell

Nickname: “Roads” Function: The internal delivery system of the cell 2 Types: _________

Endoplasmic reticulum Rough ER Smooth ER

Nickname: The shippers Function: packages, modifies, and transports materials to different location inside/outside of the cell Appearance: stack of pancakes

Golgi Apparatus

 Nickname: “Clean-up Crews” Function: to break down food into particles the rest of the cell can use and to destroy old cells.

Lysosomes

 membranous sacs of oxidase & catalase enzymes;  detoxify alcohol & neutralize dangerous free radicals.

Peroxisomes

Characteristics of plant cells

Have a cell wall and cell membranes Have a large vacuole unlike the animal cell which only has small vacuoles Have mitochondria to convert sugar to usable energy for the cell Have a few lysosomes Are more rectangular in shape Have chloroplasts to carry out photosynthesis Make sugar to store solar energy

Function: stores water This is what makes lettuce crisp When there is no water, the plant wilts

Vacuoles

Function: traps energy from the sun to produce food for the plant cell Green in color because of chlorophyll, which is a green pigment

Chloroplast

Function: provides support and protection to the cell membrane Found outside the cell membrane in plant cells

Cell wall

Summary of differences of prokaryotic and eukaryotic cells

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It is the major fuel for all cell activities that require energy

ATP