Chapter 7 final Biology

What is Passive Transport?

Requires NO energy, Movement of molecules from high to low concentration, Moves with the concentration gradient

Who was the man who came up with the name for cells, and what did he use to look at what?

Robert Hooke used an early compound microscope to look at a nonliving thin slice of cork

Most microscopes use ____ to magnify of an object by focusing _____ or ______.

lenses; light; electrons

Golgi Apparatus

modifies, sorts, and packages proteins and lipid for storage or transport out of the cell

What does the cell theory state?

1. All living things are made up of cells 2. Cells are the basic units of structure and function in living things 3. New cells are produced from existing cells

How big is Chaos chaos?

1000 micrometers (1 millimeter) in diameter

What is equilibrium?

A balanced condition resulting from two opposing reactions

What is a Prokaryotic cell?

A cell that does not enclose its DNA in a nucleus

What is a Eukaryotic cell?

A cell that encloses its DNA in a nucleus

Electron Microscope

A microscope that uses a beam of electrons instead of light to magnify objects up to 500,000 times actual size. Electron microscopes have a much higher resolving power (higher clarity) than light microscopes because of the use of electrons instead of light. Electron microscopes allow scientists to view structures within a cell. Electron microscopes can only view dead specimens. Two types of electron microscopes: 1. Scanning Electron Microscope (SEM) 2. Transmission Electron Microscope (TEM)

What type of material is cork?

A plant material

What is a cell wall?

A strong supporting layer around the membrane known as a cell wall

What is the disadvantage of an electron microscope?

Because it cannot be used to view live specimens.

Why can you not use electron microscopes to view live specimens?

Because the process used to prepare the specimen to be viewed would kill the specimen.

Why is maintaining homeostasis particularly important to single-celled organisms?

Because they consist of only one cell, loss of homeostasis by a single-celled organism. They do not have any other cells that can perform the activities of life for them.

Lysosomes

Break down and recycle macromolecules

What do lysosomes do?

Break down lipids, carbohydrates, and proteins into small molecules that can be used by the rest of the cell.

Animal cells do not have ________.

Cell walls

What is the name of the areas that hold adjacent cells together and enable them to communicate?

Cellular junctions

What is the biggest amoeba?

Chaos chaos

What form do chromosomes take for most of the time and what are they like?

Chromatin, threadlike

What type of microscope would you use to view the larger cells of plants and animals?

Compound light microscope

Nucleus

Contains DNA

What do all cells at some point in their lives?

DNA

What type of microscope would you use to view an organ that does not require much magnification?

Dissecting microscope

What type of microscope would you use to view viruses, molecules, atoms, proteins, and the smallest bacteria?

Electron microscope

Where were the organisms from Leeuwenhoek's study found?

Everywhere: In the water he drank, in his own mouth

What did Anton van Leeuwenhoek use, and what did he observe?

He used a single-lens microscope, and he observed pond water and other things

Who was Theodor Schwann?

He was a german biologist that stated that all animal are made of cells?

Who was Matthias Schleiden?

He was a german botanist that concluded that all plants are made of cells

The term... refers to the relatively constant internal physical and chemical state of a living cell.

Homeostasis

Magnification

How much larger an image appears

Where are chromosomes found?

In the nucleus

Robert Hooke

Invented the compound light microscope. Viewed a slice of cork made of empty chambers which he called "cells."

Antone Van Leeuwenhoek

Invented the single-magnifying lens microscope. First to view microscopic cells: blood and bacteria

What did Anton van Leeuwenhoek's study reveal?

It revealed that there was a fantastic world of tiny living organisms that seem to be everywhere

What did Robert Hooke notice about the cork under the microscope?

It was made out of thousands of tiny empty chambers

Macroscopic

Large enough to be visible to the naked eye.

What do we know about cells today that Robert Hooke did not?

Living cells are not chambers, but in fact they contain a huge array of working parts, each with its own function

What breaks down organelles that outlive their usefulness?

Lysosomes

Transmission Electron Microscope (TEM)

Mainly used for studying internal structures of cells. Image created is 2-D. Electromagnets magnify the image by passing a beam of electrons through a thin specimen.

Cytoskeleton

Maintains cell shape, moves cell parts. helps cells move

What does selectively permeable mean?

Meaning that some substances can pass across them and others cannot

Resolving power

Measurement of the clarity of an object

What is Diffusion?

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

What is Facilitated Diffusion?

Movement of specific molecules across cell membranes through protein channels

What are the smallest bacteria?

Mycoplasma

Do prokaryotic cells separate their genetic material within a nucleus?

No.

What do nuclei contain in a small dense region?

Nucleolus

Prokaryotic cells have cytoplasm, but no _____.

Nucleus

What can the human eye see?

Objects larger than about 0.5 millimeters

How big are Mycoplasma?

Only 0.2 micrometers across

What happens when equilibrium is reached?

Particles of a solution continue to move across the membrane in both directions

What does a microscope do?

Produces an enlarged image of something very small

What type of microscope would you use to view minute details of the surface of a leaf?

Scanning electron microscope

Vacuoles and Vesicles

Stores materials

What are organelles?

Structures inside of the cells that act as specialized organs, literally "little organs"

Stage

Supports the slide that contains the viewed specimen

Dissecting Microscope

The dissecting microscope is a light microscope that uses low magnification. Magnifies up to 40x. The dissecting microscope is used to view larger organisms, organs, tissues, and small objects that can be seen with the naked eye but need more magnification to view details.

What is the advantage of using an electron microscope instead of a light microscope?

The electron microscope gives much higher clarity of the specimen being viewed than the light microscope can; therefore, internal structures of cells can be viewed in much more detail.

Compound Light Microscope

The most commonly used. Magnifies from 40x up to 1,000x. Specimens can be dead or alive. The compound light microscope can be used with a dye on the slide to view tissue samples, blood, microorganisms in pond water, microscopic cells. The microscope allows light to pass through a specimen and uses two lenses to form an image.

What is the cytoplasm?

The portion of the cell outside the nucleus

What do chromosomes do?

They carry the cell's genetic information

Microscopic

Too small to be viewed by the naked eye.

What type of microscope would you use to view a cell's internal structures?

Transmission electron microscope

Scanning Electron Microscope (SEM)

Useful for studying details of a specimen's surface. Image is in 3-D. An electron beam passes over the specimen's surface and displaces electrons, which are then focused on a screen to form an image. Uses a conductive material (gold metal) on the specimen.

What is a lipid bilayer?

a double layered sheet that gives cell membranes a flexible structure that forms a strong barrier between the cell and its surroundings

What can you compare a cell to?

a factory

What is the cell theory?

a fundamental concept of biology

organ system

a group of organs that work together to perform a specific function

Tissue

a group of similar cells that performs a particular function

organ

a group of tissues working together to perform an essential task

What is a nucleus?

a large membrane enclosed structure that contains genetic material in the form of DNA and controls many of the cell's activities

What is DNA?

a molecule that carries biological information

What is the nucleus enclosed in?

a nuclear envelope composed of two membranes

What is the cell membrane also called?

a plasma membrane

What moves through the nuclear pores, to and from the rest of the cell?

a steady stream of proteins, RNA, and other molecules

What are all cells surrounded by?

a thin, flexible barrier called a cell membrane

Some unicellular eukaryotes, called...., contain chloroplasts

algae

Endoplasmic Reticulum

assembles proteins and lipids

Unicellular prokaryotes, called..., a adapted to living in a remarkable number of different places.

bacteria

What do we now call the organisms that Leeuwenhoek found in his mouth?

bacteria

Why is the cell membrane sometimes called a plasma membrane?

because the cells in the body are in direct contact with the fluid portion of the blood- the plasma

What is a receptor?

bonds with a signaling molecule to respond to the chemical signal

Where does the assembly of ribosomes begin?

in the nucleolus

Cells of multicellular organisms are...

interdependent and specialized become specialized for particular tasks and communicate with one another to maintain homeostasis

How do single-celled organisms maintain homeostasis?

by growing, responding to their environment, transforming energy, and reproducing.

What are attached to these proteins?

carbohydrates

single celled organisms must be able to...

carry out all the functions necessary for life

What is the smallest part of any living thing that still counts as being alive?

cell

What is the basic unit of life?

cells

What did Robert Hooke call what he saw under the microscope and why?

cells because the little compartments reminded him of a monastery's tiny rooms, which were called cells

The cells of multicellular organisms communicate with one another by means of __________.

chemical signals that are passed from one cell to another

Mitochondria

convert chemical energy in food to usable compounds

Chloroplasts

convert solar energy to chemical energy stored in food

What are the two main parts of a cell?

cytoplasm and nucleus

What can several glass lenses in combination magnify?

even the smallest objects to make them easy to see

Cells can only be produced from the division of ________.

existing cells

Who discovered that several glass lenses in combination could magnify even the smallest objects to make them easy to see, and when and where?

eyeglass makers in the late 1500s in Europe

true or false: prokaryotic cells are bigger than eukaryotic cells

false

What do proteins embedded in the lipid bilayer do?

float among the lipids

How big are typical cells

from 5 to 50 micrometers in diameter

yeasts are unicellular..., which are eukaryotes

fungi

Unicellular oganisms maintain..., relatively constant internal conditions, by growing, responding to the environment, transforming energy, and reproducing

homeostasis

Cells form connections to ___________.

neighboring cells

In eukaryotic cells the _____ separates the genetic material from the rest of the cell.

nucleus

How did we find that cells were the basic units of life?

observations by scientists

Sometimes a single cell is an...

organism

Centrioles

organize cell division

Unicellular organisms include both...

prokaryotes and eukaryotes

other unicellular eukaryotes include...and algae

protozoans

Cell Membrane

regulates materials entering and leaving cell; protects and supports cell

What were the first true microscopes made out of?

several glass lens layers

Cell Wall

shapes, supports, and protects the cel

Ribosomes

synthesize proteins

What dramatic advance in technology allowed for the discovery of the cell?

the invention of the microscope

What do the pores in the nuclear envelope do?

they allow material to move into and out of the nucleus

What is the nuclear envelope dotted with?

thousands of nuclear pores

What is the function of the cell wall?

to support, shape, and protect the cell

What are protists?

unicellular organisms

What was needed to make cells believable to science?

visibility

What does the falling of a cell into one or the other category depend on?

whether they have a nucleus or not