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Flashcards in Chapter 4- A Tour Of The Cell Deck (74):
1

Cell theory

States that all living things are composed of cells and that all cells come from earlier cells.

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Prokaryotic cells

Bacteria
Archaea

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Eukaryotic cells

Protists
Plants
Fungi
Animals

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Plasma membrane

( encloses cytoplasm) Thin double layer of lipids and proteins that regulates the traffic of molecules between the cell and its surroundings; consists of a phospholipid bilateral in which proteins are embedded.

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Cytosol

Thick, jellylike fluid in which cellular components are suspended.

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Chromosomes

All cells have one or more chromosomes carrying genes made of DNA.

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Ribosomes

(Synthesize proteins) A cellular structure consisting of RNA and proteins organized into two subunits and functioning as the site of protein synthesis of the cytoplasm; build proteins according to instructions from the genes. The ribosomal subunits are constructed in the nucleus an then they transported to the cytoplasm where they act.

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Organelles

little organs”), membrane-enclosed structures that perform specific functions within a eukaryotic cell

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Nucleus

The most important organelle, which houses most of a eukaryotic cell’s DNA.

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Nucleoid

A prokaryotic cell lacks a nucleus; its DNA is coiled into a “nucleus-like” region called the nucleoid, which is not partitioned from the rest of the cell by membranes.

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Capsule

(Sticky coating) - Capsule provide protection and help prokaryotes stuck to surfaces and other cells in a colony.

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Pili

(Attachment structures) Short projections that can attach to surfaces.

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Flagella

(Propulsion)Long projections that propel prokaryotic cells with an undulating, whiplike motion through their liquid

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Cell wall

( provides rigidity)

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Cytoplasm

The region of the cell outside the nucleus and wishing the plasma membrane that consists of various organelles suspended in the liquid cytosol.

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Phospholipids

Each phospholipid is composed of two distinct regions—a “head” with a negatively charged phosphate group and two nonpolar fatty acid “tails.”

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Phospholipid bilayal

group together to form a two-layer sheet ; the phospholipids’ hydrophilic (“water-loving”) heads are arranged to face outward, exposed to the aqueous solutions on both sides of a membrane. Their hydrophobic (“water-fearing”) tails are arranged inward, mingling with each other and shielded from water.

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Fluid mosaic

fluid because the molecules can move freely past one another and mosaic because of the diversity of proteins that float like icebergs in the phospholipid sea.

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Extracellular matrix

Animal cells lack a cell wall, but most animal cells secrete a sticky coat -Fibers made of the protein collagen (also found in your skin, cartilage, bones, and tendons) hold cells together in tissues and can also have protective and supportive functions.

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Cell junctions

structures that connect cells together into tissues, allowing the cells to function in a coordinated way.

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Capsule

(Sticky coating) - Capsule provide protection and help prokaryotes stuck to surfaces and other cells in a colony.

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Pili

(Attachment structures) Short projections that can attach to surfaces.

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Flagella

(Propulsion)Long projections that propel prokaryotic cells through their liquid.

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Cell wall

( provides rigidity)

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Cytoplasm

The region of the cell outside the nucleus and wishing the plasma membrane that consists of various organelles suspended in the liquid cytosol.

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Phospholipids

Each phospholipid is composed of two distinct regions—a “head” with a negatively charged phosphate group and two nonpolar fatty acid “tails.”

27

Phospholipid bilayer

group together to form a two-layer sheet ; the phospholipids’ hydrophilic (“water-loving”) heads are arranged to face outward, exposed to the aqueous solutions on both sides of a membrane. Their hydrophobic (“water-fearing”) tails are arranged inward, mingling with each other and shielded from water.

28

Fluid mosaic

fluid because the molecules can move freely past one another and mosaic because of the diversity of proteins that float like icebergs in the phospholipid sea.

29

Extracellular matrix

Animal cells lack a cell wall, but most animal cells secrete a sticky coat -Fibers made of the protein collagen (also found in your skin, cartilage, bones, and tendons) hold cells together in tissues and can also have protective and supportive functions.

30

Cell junctions

structures that connect cells together into tissues, allowing the cells to function in a coordinated way.

31

Describe the structure of the plasma membrane, including an explanation of why we describe it as a phospholipid bilayer and a fluid mosaic.

Membranes are not static sheets of molecules locked rigidly in place, however. In fact, the texture of a cellular membrane is similar to salad oil. The phospholipids and most of the proteins can therefore drift about within the membrane. Thus, a membrane is a fluid mosaic—fluid because the molecules can move freely past one another and mosaic because of the diversity of proteins that float like icebergs in the phospholipid sea.

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Nuclear envelope

A double membrane that separates the nucleus from the cytoplasm.

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Nuclear pores

Pores in the envelope that allow certain materials to pass between the nucleus and the surrounding cytoplasm. Some of the most important materials that pass by the pores are molecules of RNA that carry instructions for building proteins.

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Chromatin

Fibers formed by long DNA molecules and associated proteins.

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Nucleolus

A prominent structure within the nucleus, is the site where the components of ribosomes are mAde.

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Ribosomes

Protein synthesis

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Vesicle

A membranous sac in the cytoplasm of a eukaryotic cell

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Endomembrane system

This system includes the nuclear envelope, the endoplasmic reticulum, the Golgi apparatus, lysosomes, and vacuoles.

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Endoplasmic reticulum

One of the main manufacturing facilities within the cell. It has an outer nuclear membrane and composed of ribosome-studded (rough) and ribosome-free (smooth) regions.

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Rough ER

Studded with ribosomes that make membrane proteins and secretory proteins. Contracts membranes from phospholipid and proteins.

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Smooth ER

Lacks ribosomes, enzymes embedded in the smooth er function in the synthesis of certain kinds of molecules, such as lipids

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Golgi apparatus

Detailing facility that receives shipments of newly manufactured cars (proteins), puts on the finishing touches, stores the complete card, and then ships then out when needed.

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Lysosomes

A membrane enclosed sac of digestive enzymes found in animal cells.

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Vacuoles

Large sacs made of membrane that bud off from the ER or Golgi apparatus.

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Central vacuole

A versatile compartment that can account for more than half the volume of a mature plant cell.

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Chloroplasts

Unique to the photosynthetic cells of plants and algae, are the organelles that perform photosynthesis.

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Photosynthesis

The conversion of light energy from the sun to the chemical energy of sugar and other organic molecules.

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StormA

A thick fluid found inside the innermost membrane of a chloroplast.

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Grana

A chloroplasts solar power packs, the structures that trap light energy and convert it to chemical energy.

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Mitochondria

The organelles in which cellular respiration takes place.

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Cellular respiration

Energy is harvested from sugars and transformed into another form of chemical energy called ATP

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Matrix

Inner membrane of the mitochondria encloses a thick fluid.

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Cristae

The inner membrane of the envelope in a mitochondria has numerous unfolding a called cristae and they create a large surface area in which many of the enzymes and other molecules that function in cellular respiration are embedded, thereby maximizing ATP output.

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Cytoskeleton

A network of protein fibers extending throughout the cytoplasm. Act as skeleton and muscles for the cell functioning in support and movement

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Microtubules

Hollow tubes of protein

56

Intermediate filaments & microfilaments

Thinner and solid tubes

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Microtubules

Hollow tubes of protein that Guide the movement of chromosomes when cells divide

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Cilia

Shorter and more numerous than flagella and move in a coordinated back and fourth motion, like the rhythmic oars of a crew team.

59

Categorize organisms as either unicellular or multicellular based on either their domain or kingdom

Prokaryotes and Protista: single celled

Plants, animals, and most fungi: multicellular

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Magnification

The action or process of magnifying something or being magnified, especially visually.

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Resolving power

The ability of an optical instrument or type of film to separate or distinguish small or closely adjacent images.

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Food vacuole

A vacuole with. Describe function in the protoplasm of a protozoan

63

Explain how a light microscope works and identify the two most important factors in microscopy

Light is caused to pass through an object and is then focused by the primary and secondary lens. Using precise made glass lenses, takes the minutely separated light rays coming from something tiny and spreads them apart so they appear to be coming from. Much bigger object!
2 most important factors: resolution &

64

Explain how an electron microscope works and compare and contrast with a light microscope. What are the benefits and disadvantages of each?

Identical in concept to the modern light microscope. It is composed of a light source (electron source), a sub stage condenser to focus the electrons on the specimen, and an objective and ocular lens system. In the electron microscope, the ocular lens is replaced with. Projection lens, since it projects an image onto a fluorescent screen or a photographic plate. Since electrons do not pass through glass, they are focused by electro-magnetic fields. Instead of rotating a nose-piece with different fixed lenses, the EM merely changes the current and voltage applied to the electromagnetic lenses.

Electron has the ability for quantifiable mapping of surface detail, along with improved resolution and its ability to show 3D structures that light cannot.

65

Compare and contrast a scanning electron microscope with a transmission electron microscope. Under what circumstances would one choose to use one over the other?

Transmission Electron Microscopes can produce images that have Higher Magnification and Greater Resolution.
***Best for:
Looking at internal structure of objects
Looking at objects at very high resolution
Looking at relationships between structures at high resolution

Scanning Electron Microscopes produce three-dimensional (3D) images while Transmission Electron Microscopes only produce flat (2D) images.
***Best for:
Looking at surfaces of objects
Looking at objects in 3D

66

Describe what features prokaryotic and eukaryotic cells have in common.

Both prokaryotic cells and eukaryotic cells have cytoplasm, cell membrane and genetic material in common.

67

Describe what features differentiate prokaryotic and eukaryotic cell ?

The main difference is that the eukaryotic cells contain cellular organelles that are membrane bound, like the nucleus. And The prokaryotic cells do not. The cellular structure of the prokaryotes and eukaryotes differ in the presence of cellular structures like the mitochondria and chloroplasts, cell wall and the structure of chromosomal DNA.

68

List all the organelles found in an animal cell and in a plant cell. Which are found in animal cells but not in plants? Vice versa


Cell wall: absent (animal)
Plastids: absent (animal)
Centrosomes: absent (plant)
Chloroplast: absent (animal)

69

Explain how the property amphipathic affects the behavior of phospholipids when placed in water

The bilayer structure shields the hydrophobic tails of the phospholipids from water while exposing the hydrophilic heads to water.

70

What distinguishes a free ribosome from a bound ribosome?

Free ribosomes are located in the cytoplasm and produce proteins.

Bound ribosomes are attracted to the endoplasmic reticulum and they produce ribosomes that Rs transported out of the cell.

71

How does DNA direct protein production?

DNA is wrapped around proteins inside the nucleus. A single protein attaches to the unwrapped part of DNA and protein to create MRNA. When the RNA is ready it will travel to the cytoplasm. Now a ribosome will attach itself and rides all along the protein to finish that creation.

72

Describe how all the organelles of the endomembrane system are related.

By being directly continuous with one another or by sending one another vesicles. They also export. A series of compartments that work together to package, label, and ship proteins and molecules.

73

What benefit is derived from having lysosomes.

The advantage of having lysosomes is that new amino acids do not have to be made from scratch or taken up from the environment. The cell is able to produce its own building blocks when resources are scarce or its under stress because of damage from the environment.

74

Which two eukaryotic organelles contain their own DNA

Mitochondria and chloroplasts