Chapter 4 ( A Tour Of The Cell)

Front 1

What is a light microscope?

Back 1

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

Front 2

What is magnification?

Back 2

increase in the apparent size of an object

Front 3

What is a micrograph?

Back 3

photo taken through a microscope

Front 4

What is cell theory?

Back 4

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

Front 5

What is an electron microscope?

Back 5

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

Front 6

What is scanning electron microscope?

Back 6

microscope that uses an electron beam to study the fine details of cell surfaces or other specimens.

Front 7

What is a transmission electron microscope?

Back 7

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

Front 8

light microscope

Back 8

What type of microscope would be used to study the change in shape of a living human white blood cell?

Front 9

scanning electron microscope

Back 9

What type of microscope would be used to study the finest details of surface texture of a human hair?

Front 10

transmission electron microscope

Back 10

What type of microscope would be used to study the detailed structure of an organelle in a liver cell?

Front 11

What is a plasma membrane?

Back 11

- membrane at the boundary of every cell that acts as a selective barrier to the passage of ions and molecules into and out of the cell.
- consists of a phospholipid bilayer with embedded proteins.

Front 12

What are prokaryotic cells?

Back 12

- cell lacking a membrane enclosed nucleus and other membrane enclosed organelles.
- in domains; bacteria and archaea

Front 13

What is eukaryotic cells?

Back 13

- cell has membrane enclosed nucleus and other membrane enclosed organelles
- composes all organisms except bacteria and archaea

Front 14

What are chromosomes?

Back 14

- threadlike, gene carrying structure found in the nucleus of a eukaryotic cell and most visible during mitosis and meiosis
- main gene carrying structure of a prokaryotic cell
- consists of a very long piece of chromatin, combo of DNA and protein

Front 15

What are ribosomes?

Back 15

- cell structure consisting of RNA and protein organized into 2 subunits and functioning as the site of protein synthesis in the cytoplasm
- in eukaryotic cells, they are constructed in the nucleolus.

Front 16

What is a cytoplasm?

Back 16

- contents of a eukaryotic cell between the plasma membrane and the nucleus.
- consists of a semifluid medium and organelles
- refers to the interior of a prokaryotic cell

Front 17

What are the basic features of all cells?

Back 17

- bounded by a plasma membrane
- all have 1 or more chromosomes carrying genes mad up of DNA
- contain ribosomes
- interior called cytoplasms

Front 18

What is a nucleoid?

Back 18

dense region of DNA in a prokaryotic cell.

Front 19

What is a flagella?

Back 19

- long cellular appendage specialized for locomotion
- the ones in prokaryote and eukaryotes differ in both structure and function
= like cilia, eukaryotic flagella have a 9+2 arrangement of microtubules, covered by the cell's plasma membrane

Front 20

What 3 features are common to prokaryotic and eukaryotic cells?

Back 20

- plasma membrane
- chormosomes
- ribosomes

Front 21

- prokaryotic cells are smaller
= don't have nucleus that house their DNA
= no membrane enclosed organelle
= smaller, somewhat different ribosomes

Back 21

What 3 features differ between prokaryotic and eukaryotic cells?

Front 22

What is an organelle?

Back 22

membrane-enclosed structure with a specialized function within a cell

Front 23

- nucleus and ribosome carry out genetic control of the cell
- those involved in the manufacture, distribution, and breakdown of molecules include; the endoplasmic reticulum, golgi apparatus, lysosomes, vacuoles, and peroxisomes.
- mitochondria in all cells and chloroplasts in plant cells function in energy processing
- structural support, movement, and communication between cells are the functions of the cytoskeleton, plasma membrane, and plant cell wall

Back 23

What are the 4 basic functional groups organelles and other structure of Eukaryotic cells?

Front 24

What is cellular metabolism?

Back 24

all the chemical activities of a cell

Front 25

What is nucleus?

Back 25

- atom's central core, containg protons and neutrons
- genetic control center of a eukaryotic cell

Front 26

What is a chromatin?

Back 26

- combination of DNA and proteins that constitutes eukaryotic chromosomes
- often used to refer to the diffuse, very extended form taken by chromosomes when a cell isn't dividing.

Front 27

What is a nuclear envelope?

Back 27

- double membrane that encloses the nucleus, perforated with pores that regulate traffic with the cytoplasm
- separate phopholipid bilayers with associated proteins

Front 28

What is a nucleolus?

Back 28

structure within the nuclues where ribosomal RNA is made and assembled with proteins imported from the cytoplasm to make ribosomal subunits.

Front 29

- to house and copy DNA and pass it on to daughter cells in cell division
- build ribosomal subunits
- transcribe DNA instructions into RNA and therby control the cell's function
What is the main function of the nucleus?

Back 29

What is the main function of the nucleus?

Front 30

ribosomes syntehsize proteins according to the isntructions carried by messenger RNA from the DNA in the nucleus.

Back 30

What roles do ribosomes play in carrying out the gentic instructions of a cell?
ribosomes syntehsize proteins according to the isntructions carried by messenger RNA from the DNA in the nucleus.

Front 31

What is the endomembrane system?

Back 31

network of membranes inside and around a eukaryotic cell, relating either through direct physical contact or by the transfer of membranous vesicles

Front 32

What is a vesicle?

Back 32

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

Front 33

What is an endoplasmic reticulum?

Back 33

extensive membranous network in a eukaryotic cell, continuous with the outer nuclear membrane and composed of ribosome-studded and ribosome-free regions

Front 34

What is smooth endoplasmic reticulum?

Back 34

portion of the endoplasmic reticulum that lacks ribosomes

Front 35

WHat is rough endoplasmic reticulum?

Back 35

portion of the endoplasmic reticulum with ribosomesattached that make membrane proteins and secretory proteins

Front 36

What is a glycoprotein?

Back 36

protion with 1 or more short chains of sugars attached to it

Front 37

What is a transport vesicle?

Back 37

- small membranous sac in eukaryotic cells cytoplasm carrying molecules produced by the cells
- vesicle buds from the endoplasmic reticulum or golgi and eventually fuses with another organelle or plasma membraen releasing its contents

Front 38

- it porduces a huge variety of molecuels, including phospholipids for cell membranes, steroid hormones, and proteins (synthesized by bound proteins) for membranes, other organelles, and secretion by the cell.

Back 38

Why is the endoplasmic reticulum called a biosynthetic factory?

Front 39

- golgi receives transport vesicles that bud from the ER and that contain proteins synthesized by ribosomes attached to the ER.
- Golgi finishes processing the proteins and then dispatches transport vesicles that secrete proteins to the outside of the cell

Back 39

What is the relationship of the golgi apparatus to the ER in a protein secreting cell?

Front 40

What is a lysosome?

Back 40

- digestive organelle in eukaryotic cells
- contains hydolytic enzymes that digest engulfed food or damaged organelles.

Front 41

it breaks down damaged organelles and recycles their molecules.

Back 41

How is a lysosome like a recycling center?

Front 42

What is a vacuoles?

Back 42

membrane-enclosed sac that is part of the endomembrane system of a eukaryotic cell and has diverse function

Front 43

What is a central vacuole?

Back 43

in a plant cell, a large membranous sac with divrse roles in growth and the storage of chemicals and waste.

Front 44

yes, it forms by pinching in from the plasma membrane, which is part of the endomembrane system

Back 44

Is a food vacuole part of the endomembrane system?

Front 45

What are peroxisomes?

Back 45

organelle containing enzymes that transfer hydrogen atoms from various substances to oxygen, producing and then degrading hydrogen peroxide.

Front 46

transport vesicles move membranes and substances they enclose between components of the endomembrane system.

Back 46

How do transport vesicels help tie together the endomembrane system?

Front 47

What is mitochondria?

Back 47

- an organelle in eukaryotic cells where cellular respiration occurs
- enclosed by 2 membranes, it's where most of the cell's ATP is made.

Front 48

What is a mitochondrial matrix?

Back 48

compartment of the mitochondrion enclosed by the inner membrane and containing enzymes and substrates for the citric acid cycle.

Front 49

What is cristae?

Back 49

an infolding of the innermitochondrial membrane.

Front 50

What is cellular respiration?

Back 50

process that converts the chemical energy of sugars and other food molecules ot the chemical energy of ATP.

Front 51

What are chloroplasts?

Back 51

organelle found in plants and photosynthetic protists that absorbs sunlight and uses it to drive the synthesis of organic molecules (sugars) from carbon dioxide and water

Front 52

What is stroma?

Back 52

- dense fluid within the chlorplast that surrounds the thykaloid membrane and is involved in synthesis of organic molecules from carbon dioxide and water.
- sugars are made in here by enzymes of the Calvin cycle.

Front 53

What are thylakoids?

Back 53

- flattened membranous sac inside a chloroplast
- contain chlorophyll and the molecular complexes of the light reaction of photosynthesis.
- stack of them is called a granum

Front 54

What is granum?

Back 54

- stack of membrane-bounded thylakoids in a chloroplast
- site where light energy is trapped by chlorophyll and converted to chemical energy during the light reaction of photosynthesis.

Front 55

thylakoid membranes are most extensive providing a large area of membranes that contains chlorophyll for photosynthesis.

Back 55

Which membrane in a chloroplast appears to be the most extensive, and why?

Front 56

What is an endosymbiont theory?

Back 56

- theory that mitochondria and chloroplasts originated as prokaryotic cells engulfed by an ancestral eukaryotic cell.
= engulfed cell and its host cell then evolve into a single
organism

Front 57

1st endosymbiotic event would have given rise to eukaryotic cells containing mitochondria. At least 1 of them may have then taken up a photosynthetic prokaryote, giving rise to eukaryotic cells that contain chloroplasts in addition to mitochondria.`

Back 57

All eukaryotes have mitochondria, but not all eukaryotes have chloroplast. Why might this be?

Front 58

What is a cytoskeleton?

Back 58

- network of protein fibers in the cytoplasm of a eukaryotic cell.
- includes; microfilaments, intermediate filaments, and microtubules

Front 59

What are microfilaments?

Back 59

- thinnest of the 3 kinds of protein fibers making up the cytoskeleton of a eukaryotic cell.
- solid, helical compound of the globular protein actin.

Front 60

What are intermediate filaments?

Back 60

- intermediate-sized protein fiber that is 1 of the 3 main kinds of fibers making up the cytoskeleton of eukaryotic cells.
- ropelike, made of fibrous proteins.

Front 61

What are microtubules?

Back 61

- thickest of the 3 main kinds of fibers making up the cytoskeleton of a eukaryotic cell
- hollow tube made of globular proteins called tubulins.
- found in cilia and flagella

Front 62

intermediate filaments.

Back 62

What component of the cytoskeleton is most important in holding the nucleus in place within the cells.

Front 63

microtubules

Back 63

Which component of the cytoskeleton is most important in guiding transport vesicles from the golgi to the plasma membrane?

Front 64

microfilaments

Back 64

Which component of the cytoskeleton is most important in containing muscle cells?

Front 65

What are cilia?

Back 65

- short celluar appendage specialized for locomotion
- formed from a core of 9 outer doublet microtubules and 2 single microtubules (9+2) pattern covered by the cell's plasma membrane.

Front 66

- both have the (9+2) pattern of microtubules and mechanism for bending.
- different
= cilia are shorter, more numerous, and beat in a
coordinated oar like patern
= longer flagella, which are limited to 1 or a few per cell
, undulate like a whip.

Back 66

Compare and contrast cilia and flagella.

Front 67

both have the same arrangement of microtubules doublets with attached dynein motor proteins that cause them to bend.

Back 67

Why does a lack of dynein proteins affect the action of both cilia and flagella?

Front 68

What is an extracellular matrix?

Back 68

- mesh work surrounding animal cells
- consists of glycoproteins and polysaccharides

Front 69

What are integrins?

Back 69

transmembrane protein that interconnects the extracellular matrix and the cytoskeleton.

Front 70

anchoring junction

Back 70

A muscle tear injury would probably involve the rupture of which type of cell juntion?

Front 71

What are tight junctions?

Back 71

plasma membranes of neighboring cells are tightly pressed against each other and knit together by proteins.

Front 72

What are anchoring junctions?

Back 72

- function like rivets, fastening cells together into strong sheets
- common to tissues subject to stretching of mechanical stress
EX: skin and heart muscles

Front 73

What are gap junctions?

Back 73

- aka communicating junctions
- channels that allow small molecules to flow through protein lined pores between cells.

Front 74

What is a cell wall?

Back 74

- protective layer external to the plasma membrane in plant cells, bacteria, fungi, and some protists.
- protects the cells and helps maintain its shape.

Front 75

What is plasmodesmata?

Back 75

an open chennel in a plant cell wall through whcih strands of cytoplasms connect from adjacent cells.

Front 76

a gap junction

Back 76

What animal cell junction is analogous to a plasmodesma?

Front 77

- mitochondria supply energy in the form of ATP
- smooth ER helps regulate contraction by the uptake and release of calcium ions
- microfilaments function in the actual contractile apparatus

Back 77

How do mitochondria, smoother ER, and the cystoskeleton contribute to the contraction of a muscle cell?

Front 78

The ultrastructure of a chloroplast is best studied using what?

Back 78

transmission electron microscope

Front 79

rough ER > golgi > transport vesicle > plasma membrane

Back 79

A type of cell called a lymphocyte makes proteins that are exported from the cell. What is the path of a protein from the site where its polypeptides are made to its exports?