Chapter 6 AP Biology

Nucleus

(1) An atom's central core, containing protons and neutrons. (2) The organelle of a eukaryotic cell that contains the genetic material in the form of chromosomes, made of chromatin.

Apoptis

(ā-puh-tō´-sus) The timely and tidy suicide of cells; also called programmed cell death.

Describe the process of cell fractionation

1. Tissue is cut into pieces and placed in a cold, buffered, isotonic solution (the solution kills the cells) 2. Tissue is homogenised 3. Homogenate is filtered 4. Centrifuged at different speeds

The extracellular matrix of the animal cell has all of the following molecular components except __________.

a middle lamella

nucleolus

non-membranous structure involved in the production of ribosomes; nucleus has one or more nucleoli. where ribosomal RNA is made and assembled with proteins imported from the cytoplasm to make ribosomal subunits.

The endoplasmic reticulum is part of the endomembrane system, which also includes the __________.

nuclear envelope, the Golgi apparatus, lysosomes, and vesicles

The region of a bacterial cell that contains the genetic material is called the __________.

nucleoid

Evidence that supports the prokaryotic origins of mitochondria and chloroplasts are all of the following except __________.

that mitochondria and chloroplasts have multiple copies of linear DNA molecules associated with their inner membranes

central vacuole

prominent organelle in older plant cells; functions include storage, breakdown of waste products, and hydrolysis of macro molecules; enlargement of the vacuole is a major mechanism of plant growth ****found in plant cells only****

Intracellular junctions are primarily

proteins

centrosome

region where the cell's microtubules are initiated; contains a pair of centrioles

cytoskeleton

reinforces cell's shape; functions in cell movement; components are made of protein. Includes micro filaments, intermediate filaments, and microtubles

You would expect a cell with an extensive Golgi apparatus to __________.

secrete a lot of protein

granum (grana)

stacks of thylakoids

Microfilaments function in cell motility including __________.

muscle contraction, amoeboid movement, and cytoplasmic streaming in plants

Microscopes are generally...

names after what they use to make an image

endoplasmic reticulum

network of membranous sacs and tubes; active in membrane synthesis and other synthetic and metabolic processes; has rough (ribosome-stubbed) and smooth regions

What is the highest magnification for a light microscope?

1000x

Thylakoid

A flattened membrane sac inside the chloroplast, used to convert light energy into chemical energy.

Chromosome

A gene-carrying structure found in the nucleus of a eukaryotic cell and most visible during mitosis and meiosis; also, the main gene-carrying structure of a prokaryotic cell. A chromosome consists of one very long DNA molecule and associated proteins.

Organelle

A membrane-enclosed structure with a specialized function within a cell.

transmisson electron microscope

A microscope that uses an electron beam to study the internal structure of thinly sectioned specimens.

scanning electron microscope

A microscope that uses an electron beam to study the surface details of a cell or other specimens.

electron microscope

A microscope that uses magnets to focus an electron beam through, or onto the surface of, a specimen. An electron microscope achieves a hundredfold greater resolution than a light microscope.

endomembrane system

A network of membranes inside and surrounding a eukaryotic cell, related either through direct physical contact or by the transfer of membranous vesicles.

nucleoid

A non-membrane-bounded region in a prokaryotic cell where the DNA is concentrated.

Vesicle

A sac made of membrane in the cytoplasm of a eukaryotic cell.

transport vesicles

A small membranous sac in a eukaryotic cell's cytoplasm carrying molecules produced by the cell. The vesicle buds from the endoplasmic reticulum or Golgi and eventually fuses with another organelle or the plasma membrane, releasing its contents.

prokaryotic cell

A type of cell lacking a membrane-enclosed nucleus and membrane-enclosed organelles; found only in the domains Bacteria and Archaea.

cellular metabolism

All the chemical activities of a cell.

light microscope

An optical instrument with lenses that refract (bend) visible light to magnify images and project them into a viewer's eye or onto photographic film.

chloroplast

An organelle found in plants and algae that absorbs sunlight and uses it to drive the synthesis of organic compounds (sugars) from carbon dioxide and water.

endosymbiotic theory

Ancestors of mitochondria and plastids was prokaryotes thatcame to live in a host cell.

Centrioles

Cell organelle that aids in cell division in animal cells only

Vacuole

Cell organelle that stores materials such as water, salts, proteins, and carbohydrates

In terms of cellular function, what is the most important difference between prokaryotic and eukaryotic cells?

Eukaryotic cells are compartmentalized, which allows for specialization.

Which of the following is false in respect to cells' chromosomes?

Chromosomes only appear as a cell is about to divide.

Basal bodies are most closely associated with which of the following cell components?

Cilia

Which statement about the cytoskeleton is true?

Components of the cytoskeleton often mediate the movement of organelles within the cytoplasm.

cilia

Hairlike projections that extend from the plasma membrane and are used for locomotion

Is the result from an electron microscope a live image or a snapshot? Why ?

In an electron microscope the result is a snapshot because the beams of electrons kill whatever living thing is being looked at

Stroma

In plants, the solution that surrounds the thylakoids in a chloroplast.

Brightfield

Light passes directly through specimen, can be stained or unstained

Microfilaments

Long, thin fibers that function in the movement and support of the cell

Cilia and flagella move due to the interaction of the cytoskeleton with which of the following?

Motor proteins

__________ are membrane-bound metabolic compartments that specialize in the production of hydrogen peroxide (H2O2) and its conversion to water.

Peroxisomes

Which of the following is present in a prokaryotic cell?

Ribosomes

Which of the following groups is primarily involved in synthesizing molecules needed by the cell?

Ribosomes, rough endoplasmic reticulum, and smooth endoplasmic reticulum

What determines the usage of SEM vs TEM or vice versa?

SEM is 3-D and doesn't let you look inside but TEM does let you look inside, usage depends on what you are using the microscope to see

Chromatin

Substance found in eukaryotic chromosomes that consists of DNA tightly coiled around histones

What is the functional connection between the nucleolus, nuclear pores, and the nuclear membrane?

Subunits of ribosomes are assembled in the nucleolus and pass through the nuclear membrane via the nuclear pores.

Smooth Endoplasmic Reticulum (SER)

That portion of the endoplasmic reticulum that lacks ribosomes.

Rough Endoplasmic Reticulum

That portion of the endoplasmic reticulum with ribosomes attached that make membrane proteins and secretory proteins.

cytoplasm

The contents of a eukaryotic cell between the plasma membrane and the nucleus; consists of a semifluid medium and organelles; can also refer to the interior of a prokaryotic cell.

Cristae

The folds of the inner membrane of a mitochondrion (ATP) surface area

Your intestine is lined with individual cells. No fluids leak between these cells from the gut into your body. Why?

The intestinal cells are bound together by tight junctions.

Cell Theory

The theory that all living things are composed of cells and that all cells come from other cells.

Microtubules

Thick hollow tubes that make up the cilia, flagella, and spindle fibers.

What microscope gives a better image than a brightfield (light) microscope and why?

an electron microscope because gives better resolution, greater magnification

The organelle that is a plant cell's compartment for the storage of inorganic ions such as potassium and chloride is the __________.

central vacuole

Animal cells have unique organelles called __________ that are composed of structures called __________.

centrosomes; centrioles

ribosomes

complexes the make proteins; free in cytosol or bound in the rough ER or nuclear membrane

plasmadesmata

cytoplasmic channels through cell walls that connect the cytoplasm of adjacent cells

lysosome

digestive organelle where macro-molecules are hydrolyzed

prokaryotes

don't have internal nucleus or membrane bound organelles

nuclear envelope

double membrane enclosing the nucleus; perforated by pores; continuous with ER

The total number of magnification is made of the

eyepiece and the objective

tight junctions

go all away around the membrane and contacts tight junction in another cell

Bacterial cells are prokaryotic. Unlike a typical eukaryotic cell they __________.

have no membrane-bounded organelles in their cytoplasm

Observing a fluorescent micrograph cell with intermediate filaments would help you identify the cell as a __________.

human skin cell

A protein that ultimately functions in the plasma membrane of a cell is most likely to have been synthesized __________.

in the rough endoplasmic reticulum

The walls of plant cells are largely composed of polysaccharides and proteins that are synthesized __________.

in the rough endoplasmic reticulum and in the Golgi apparatus

Because we are multicellular there are things that hold out cells together such as...

intracellular junctions, tight junctions, desmosomes, and gas junctions

The network of fibers that organizes structures and activities in a cell __________.

is the cytoskeleton

Most stains require cells to be preserved, which ________ them

kills

intermediate filament

maintenance of cell shape; anchorage of nucleus and certain other organelles formation of nuclear lamina found in the cells of some animals including vertebrates; more permanent framework. diverse class of cytoskeletal elements that bear tension like microfilaments

Eukaryotes have

membrane bound organelles

plasma membrane

membrane enclosing the cell

cilia

micro tubule-containing extensions that project from some cells, loco-motor appendage; occur in large numbers

The endosymbiont theory explains the origins of __________.

mitochondria and chloroplasts

flagellum

motility structure present in some animal cells, composed of a cluster of microtubules within an extension of the plasma membrane

Cells are small because __________.

of the geometric relationships between surface and volume

golgi apparatus

organelle active in synthesis, modification, sorting, and secretion of cell products

mitochondria

organelle where cellular respiration occurs and most ATP is generated

peroxisomes

organelle with various specialized metabolic functions; produces hydrogen peroxide as a by-product and then converts it to water. Contains enzymes that detoxifies alcohol

cell wall

outer layer that maintains cell's shape and protects cell from mechanical damage; made of cellulose, other polysaccharides, and protein ****found in plant cells only****

chloropasts

photosnthetic organelle' converts energy of sunlight to chemical energy stored in sugar molecules

Dye injected into a plant cell might be able to enter an adjacent cell through __________.

plasmodesmata

Cell junctions in plant cells are called __________, and communicating junctions in animal cells are called __________.

plasmodesmata; gap junctions

cell fractionation

the disruption of a cell and separation of its parts by centrifugation at successively higher speeds

Tight junctions are mostly in the upper layers of the body because...

the goal is to keep liquid from leaving

A substance moving from outside the cell into the cytoplasm must pass through __________.

the plasma membrane

what is the purpose of cellular junctions?

to make us water tight: the area between cells is full of aqueous solution

The function of the rough endoplasmic reticulum (RER) is __________.

to synthesize proteins that are secreted as glycoproteins

Integrins

transmembrane protein attaches the extracellular matrix and the cytoskeleton

True or false: You can use micrometers of a microscope to estimate actual size?

true

What is the difference between an unstained and stained sample in a brightfield microscope?

unstained is how it appears in nature and stained is when parts of the cell are dyed in order to make certain organelles more apparent

How long you spin the homogenate in the centrifuge and at what rate depends on...

what result you need at the bottom (i.e. nucleus, mitochondria) and the supernatant above

Cell motility, which includes changes both in cell location and in the movement of cell parts, requires interactions of the cytoskeleton __________.

with motor proteins

motor proteins function

works together with plasma membrane molecules to allow whole cells to move along fibers outside the cell, attach receptors on vesicles to "walk"