Chapter 4 - Cells & Microscopes

Question 1

Light Microscope

Answer 1

optical instrument with lenses that refract(bend) visible light to magnify images and project them into the viewer’s eye or onto photographic film. These can be used to study live specimens, but they only magnify about a thousand times.

Question 2

Magnification

Answer 2

the increase in the apparent size of an object

Question 3

resolution

Answer 3

A measure of the clarity of an image OR the ability of an optical instrument to show objects as separate

Question 4

Cell Theory

Answer 4

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

Question 5

electron microscope (EM)

Answer 5

an instrument that focuses and electron beam through (or onto the surface of) a specimen. has electromagnets as lenses and achieves 1000fold greater resolution then a light microscope but isn’t that great for studying live specimens

Question 6

Scanning electron microscope

Answer 6

microscope that uses an electron beam to study the service architecture of a cell (or other specimen). produces images that look 3-D

Question 7

transmission electron microscope

Answer 7

microscope that uses an electron beam to study the internal structure of a thinly section specimen

Question 8

prokaryotic cell

Answer 8

type of cell lacking a membrane-enclosed nucleus and other membrane-enclosed organelles.
found in bacteria and archea

Question 9

eukaryotic cell

Answer 9

type of cell that has a membrane enclosed nucleus and other membrane enclosed organelles.
found in protist, fungi, plants, and animals

Question 10

features of cells

Answer 10

• bound by a plasma membrane
• genes made of DNA as hereditary material
• contains ribosomes

Question 11

plasma membrane

Answer 11

thin layer of lipids and proteins that sets cells off from surroundings and acts as a selective barrier to pass off ions and molecules into and out of the cell.
consist of a phospholipid bilayer in which are embedded molecules of protein and cholesterol

Question 12

ribosomes

Answer 12

cell organelles consisting of RNA and protein organized into two subunits and functioning as the site of protein synthesis in cytoplasm.
constructed in the nucleolus

Question 13

nucleotide region

Answer 13

region in a prokaryotic cell where the DNA is coiled

Question 14

cell wall

Answer 14

A protective layer external to the plasma membrane in plant cells, bacteria, fungi, and some protists.
it protects and maintains the shape of the cell

Question 15

Capsule

Answer 15

sticky layer that surrounds the bacteria cell wall, protects the cell surface and sometimes helps glue the cells to the surface

Question 16

pilus

Answer 16

short projections on the surface of a prokaryotic cell that helps it to attach to surfaces. the plural is “pili”

Question 17

cytoplasm

Answer 17

Everything inside of eukaryotic cell between the plasma membrane and nucleus.
it consist of a semi fluid medium and organelles

Question 18

organelles

Answer 18

structure with a specialized function in a cell

Question 19

Cellular metabolism

Answer 19

The chemical activities of cells

Question 20

Nucleus

Answer 20

The genetic control center of the eukaryotic cell contains DNA and controls the actions of the cell by directing protein synthesis

Question 21

differences in eukaryotic plant cells

Answer 21

• rigid thick cell wall
• chloroplast
• central vacuole

Question 22

Chromatin

Answer 22

combination of DNA and proteins that constitutes chromosomes sometimes used to refer to diffuse and very extended form taken by chromosomes when a eukaryotic cell is dividing

Question 23

Chromosome

Answer 23

A threadlike gene-carrying structure found in the nucleus of eukaryotic cell and most visible during mitosis and meiosis.
also the main gene-carrying structure of prokaryotic cells

Question 24

Nuclear envelope

Answer 24

A double membrane perforated with pore that encloses the nucleus

Question 25

Nucleolus

Answer 25

A structure within a eukaryotic cell nucleus where ribosomal RNA is made and assembled with proteins to make ribosomal subunits.
consist of parts of chromatin DNA, RNA transcribed from that DNA and proteins imported

Question 26

Endomembrane system

Answer 26

A network of membranous organelles that partition the cytoplasm of a eukaryotic cells into functional compartments.
some membranes are physically connected others are related by transfer of membrane segments by tiny vesicles

Question 27

vesicles

Answer 27

Sacs made of membrane

Question 28

endoplasmic reticulum

Answer 28

extensive membranous organelles in a eukaryotic cell, continues with the outer nuclear membrane composed of ribosome studded and ribosomes free regions

Question 29

Smooth ER

Answer 29

A network of interconnected membranous tubules in the cytoplasm of a eukaryotic cell.
lacks ribosomes.
the enzymes embedded in the membrane function in the synthesis of certain kinds of molecules like lipids.
also serves as storage for calcium ions

Question 30

rough ER

Answer 30

A network of interconnected membranous sacs in the cytoplasm of a eukaryotic cell.
studded with ribosomes that make membrane secretory proteins.
constructs membrane from phospholipids and proteins.
they modify proteins that will be secreted or transported to other organelles

Question 31

Secretory proteins

Answer 31

A protein like an anti-body that is secreted by a cell