Structure of Cells

Question 1

surface-area-to-volume-ratio

Answer 1

requires that cells be small
large cells- decreases the efficiency of transporting material in and out of cells
Small cells-large surface area to volume ratio is beneficial for exchanging molecules

Question 2

compound light microscope

Answer 2

-maximum magnification of 1000x
-light passes through and is focused by glass lenses

Question 3

transmission electron microscope (TEM)

Answer 3

• electrons are passed through and focused by a set of magnetic lenses
  -100,000x

Question 4

scanning electron microscope (SEM)

Answer 4

-sprayed within a thin coat of metal
- electron beam is scanned across the surface, the surface metal emits secondary electrons
-electrons are detected and focused by magnetic lenses

Question 5

Prokaryotic cells

Answer 5

-lack membrane-bound nucleolus
-structurally smaller and simpler
-bacteria and archaea

Question 6

bacteria vs archaea

Answer 6

bacteria: causes diseases and acts as decomposers.
archaea: live in extreme habitats.

Question 7

structure of prokaryotes

Answer 7

1.spherical coccus
2. rod-shaped bacillus
3. spiral spirillum (if rigid) or spirochete (if flexible)

Question 8

cell envelopes of prokaryotes include

Answer 8

plasma membrane- lipid bilayer with embedded and peripheral proteins

Question 9

cytoplasm

Answer 9

-semifluid solution
-contains water, inorganic and organics molecules and enzymes

Question 10

nucleoid

Answer 10

a region that contains the single, circular DNA molecule

Question 11

plasmids

Answer 11

small accessory (extrachromosomal) rings of DNA

Question 12

Ribosomes

Answer 12

tiny structures in the cytoplasm that synthesize proteins

Question 13

flagella

Answer 13

provides motility

Question 14

fimbriae

Answer 14

small, bristle-like fibers that sprout from the cell surface

Question 15

conjugation pili

Answer 15

rigid tubular structures used to pass dna from cell to cell

Question 16

Eukaryotic cells

Answer 16

contains a plasma membrane that separates cell content and regulates passage of materials in and out
-membrane bound nucleus that houses DNA
-contains organelles that isolate reactions from other reactions

Question 17

Eukaryotic cell organelles are divided into 4 categories…

Answer 17

• nucleus and ribosomes
  -endomembrane system
  -energy related organelles
  -cytoskeleton

Question 18

Chromatin

Answer 18

network of fine strands that are composed of DNA, proteins, and some rna

Question 19

types of RNA

Answer 19

Messenger (mRNA)- carries the information for the amino acid sequence of a protein
Ribosomal (rRNA)- combines with specific proteins to form the subunits of ribosomes

Question 20

what separates the contents of the nucleus from the cytoplasm?

Answer 20

nuclear membrane

Question 21

what do nuclear pores do?

Answer 21

permits the passage of ribosomal subunits and mRNA out of the nucleus and proteins into the nucleus

Question 22

ribosome subunits

Answer 22

one large and one small are assembled in the cytoplasm and used to make proteins

Question 23

where are ribosomes found?

Answer 23

-prokaryotes and eukaryotes
-eukaryotic cells: single ribosomes in the cytoplasm. Attached to the endoplasmic reticulum (ER)

Question 24

ribosomes proteins

Answer 24

-used in different parts of the cells
-proteins from free ribosomes are used in the cytoplasm
-proteins from ribosomes attached to the ER are deposited in the ER

Question 25

endomembrane system components

Answer 25

1. nuclear membrane 2. endoplasmic reticulum 3. Golgi apparatus 4. vesicles

Question 26

what are Saccules?

Answer 26

membranous channels and flattened vesicles found in the ER

Question 27

what does the golgi apparatus consist of and do?

Answer 27

consist of numerous flattened saccules receives protein transport vesicles from the er and packages them in new vesicles -directs the new vesicles to the location intended for the protien

Question 28

what are lysosomes

Answer 28

Golgi vesicles which contain proteins that digest molecules or structures within the cell

Question 29

what are vacuoles?

Answer 29

membranous sacs that are larger than vesicles -vacuoles can store nutrients, ions, or other molecules

Question 30

two types of membranous organelles that specialize in energy conversion are...?

Answer 30

chloroplast: uses solar energy to synthesize carbohydrates via photosynthesis mitochondria: breaks down carbohydrates to produce ATP

Question 31

what does the stroma contain?

Answer 31

-enzymes for photosynthesis -a third set of membranes, organized as a series of disk like sacs called thylakoids

Question 32

How are thylakoids organized?

Answer 32

stacks or grana

Question 33

what is the matrix?

Answer 33

where chemical reactions products end up

Question 34

how is cristae formed and what does it do?

Answer 34

the convolutions of the inner membrane in the mitochondria form cristae -increases surface area

Question 35

cellular respiration

Answer 35

the breakdown of molecules in the presence of oxygen to produce ATP

Question 36

what are microtubules?

Answer 36

proteins arranged to form hollow cylinders -assembled by the centrosome

Question 37

what are intermediate filaments and what do they do?

Answer 37

intermediate in size between actin filaments and microtubules -ropelike polypeptides support the nucleolus and plasma membrane

Question 38

what are centrioles and what do they do?

Answer 38

short cylinders with a 9+0 pattern of microtubules triplets -involved in cell division

Question 39

cilia and flagella

Answer 39

hairlike projections that allow organisms to move -both are membrane-bound cylinders -both have a basal body in the cytoplasm