Molecular & Cell Biology (Bi 005) Chapter 6 A Tour Of The Cell

Front 1

What are Prokaryotic Cells?

Back 1

1.DNA is located in the nucleoid (region of cyto-plasm not enclosed by a membrane)
2. Organelles are few and simple
3. Cells are relatively small

Front 2

What are Eukaryotic Cells?

Back 2

DNA is located in the nucleus
2. Organelles are many and complex
3. Cell are relatively large

Front 3

Prokaryotic v. Eukaryotic Cells
What are common features?

Back 3

1.Chromosomes
2.Cytosol
3.Plasma membrane
4.Ribosomes

Front 4

Prokaryotic v. Eukaryotic Cells
What about the Cell Size?

Back 4

1.Regardless of the size of organisms, cells are ap-proximately the same size
2.Cell size is limited by surface area to volume ratio

Front 5

What is a
Cytoplasm?

Back 5

interior region of the cell between the nucleus and plasma membrane
1.Suspended in cytosol are membrane-bound organelles
2.Cytosol – fluid portion of the cell

Front 6

What is a
Plasma Membrane?

Back 6

boundary of the cell that functions as a selective barrier that allows the passage of oxygen, nutrients, and wastes

Front 7

What is a
Nucleus?

Back 7

1.Contains most of the genes in the cell
2.Generally, most conspicuous organelle

Front 8

What is a
Nuclear envelope?

Back 8

a) Complexes line the pores in the envelope regulat-ing the exit of proteins, RNA’s, macromolecules

Front 9

What is a
Nuclear lamina?

Back 9

a) Maintains the shape of the
nucleus by mechanically
supporting the envelope

Front 10

What are
Chromosomes?

Back 10

a) Located in the nucleus, carry genetic information
b)Composed of chromatin (DNA + protein complex)
c)Each spp has a distinct number of chromosomes

Front 11

What is a
Nucleolus?

Back 11

a) Synthesizes RNA as well as ribosomal
subunits which assemble into
ribosomes in the cytoplasm

Front 12

What are Ribosomes?

Back 12

1. Complexes composed of ribosomal RNA and proteins
2. Site of protein synthesis (cells that carry out much protein synthesis have many ribosomes, nucleoli)

Front 13

What are free ribosomes?

Back 13

suspended in cytosol; proteins produced here function within cytosol

Front 14

What are bound ribosomes?

Back 14

attached to outside of the endo-plasmic reticulum or nuclear envelope; proteins pro-duced here function in other areas of the cell

Front 15

What is Endoplastic Reticulum?

Back 15

1. Extensive network of membranes (accounts for more than half the total membranes in a cell)
2. Functions include protein synthesis, protein trans-port, metabolism, lipid transport, and poison detox
3. Continuous with nucleus

Front 16

Organelles of Eukaryotic Cells
Endoplastic Reticulum
What is smooth endoplastic reticulum?

Back 16

a)Outer surface lacks ribosomes
b)Drugs and alcohol increase proliferation, which increases rate of detoxification, which increases tolerances
c)Lipid synthesis, especially steroids including sex hormones and adrenal gland hormones
d)Detox of drugs (including alcohol) and poisons, especially in liver cells
e)In muscles, stores Ca ions
for muscle contractions

Front 17

What is Rough endoplastic reticulum?

Back 17

a)Outer surface is studded with ribosomes
b)Site of protein synthesis and transport, membrane construction
c)lipid synthesis, especially steroids including sex hormones and adrenal gland hormones
d)Detox of drugs (including alcohol) and poisons, especially in liver cells
e)In muscles, stores Ca ions
f)for muscle contractions (sarcoplasmic reticulum)

Front 18

What are Transport vesicles

Back 18

membranous sacs in transit from one part of the cell to another, transporting mole-cules produced by the cell through the cytoplasm

Front 19

What is the
Golgi Apparatus?

Back 19

1. Especially numerous in cells special-ized for secretions
2. Products of the ER are modified and stored in Golgi until shipped to other destinations
3. Transport vesicles transfer material from Golgi to other parts of the cell

Front 20

What are
Lysosomes?

Back 20

1.Membranous sacs of hydrolytic enzymes that an animal cell uses to digest macromolecules
2.Hydrolytic enzymes and lysosomal membranes are made by rough ER and transferred to Golgi for further processing

3.Phagocytosis: process in which large particulate substances or small organisms are taken up by a cell
4.Autophagy – process in which damaged cell parts are taken up by a cell and hydrolytic enzymes recycle the organic material back into the cytoplasm

Front 21

What is a
Nucleolus?

Back 21

a) Synthesizes RNA as well as ribosomal
subunits which assemble into
ribosomes in the cytoplasm

Front 22

What are Ribosomes?

Back 22

1. Complexes composed of ribosomal RNA and proteins
2. Site of protein synthesis (cells that carry out much protein synthesis have many ribosomes, nucleoli)

Front 23

What are free ribosomes?

Back 23

suspended in cytosol; proteins produced here function within cytosol

Front 24

What are bound ribosomes?

Back 24

attached to outside of the endo-plasmic reticulum or nuclear envelope; proteins pro-duced here function in other areas of the cell

Front 25

What is Endoplastic Reticulum?

Back 25

1. Extensive network of membranes (accounts for more than half the total membranes in a cell)
2. Functions include protein synthesis, protein trans-port, metabolism, lipid transport, and poison detox
3. Continuous with nucleus

Front 26

What is smooth endoplastic reticulum?

Back 26

a)Outer surface lacks ribosomes
b)Drug and alcohol increase proliferation, which increases rate of detoxification, which increases tolerances
c)Lipid synthesis, especially steroids including sex hormones and adrenal gland hormones
d)Detox of drugs (including alcohol) and poisons, especially in liver cells
e)In muscles, stores Ca ions
for muscle contractions

Front 27

What is Rough endoplastic reticulum?

Back 27

a)Outer surface is studded with ribosomes
b)Site of protein synthesis and transport, membrane construction
c)lipid synthesis, especially steroids including sex hormones and adrenal gland hormones
d)Detox of drugs (including alcohol) and poisons, especially in liver cells
d)In muscles, stores Ca ions
for muscle contractions (sarcoplasmic reticulum)

Front 28

What is a Transport vesicles

Back 28

membranous sacs in transit from one part of the cell to another, transporting mole-cules produced by the cell through the cytoplasm

Front 29

What is a
Golgi Apparatus?

Back 29

1. Especially numerous in cells special-ized for secretions
2. Products of the ER are modified and stored in Golgi until shipped to other destinations
3. Transport vesicles transfer material from Golgi to other parts of the cell

Front 30

What is a
Lysosomes?

Back 30

1.Membranous sacs of hydrolytic enzymes that an animal cell uses to digest macromolecules
2.Hydrolytic enzymes and lysosomal membranes are made by rough ER and transferred to Golgi for further processing

3.Phagocytosis: process in which large particulate substances or small organisms are taken up by a cell
4.Autophagy – process in which damaged cell parts are taken up by a cell and hydrolytic enzymes recycle the organic material back into the cytoplasm

Front 31

What is a
Membrane?

Back 31

bound vesicles made by the ER and Golgi which perform a variety of functions in different cells

Front 32

What is a
Food vacuole?

Back 32

membranous sac formed by phago-cytosis of microorganisms or particles to be used as food by the cell

Front 33

What is a
Contractile vacuole?

Back 33

membranous sac that assists in moving excess water out of some freshwater protists

Front 34

What is a
Central vacuole?

Back 34

in a mature plant cell, a large membranous sac with diverse roles in growth, storage, and sequestration of toxic substances

Front 35

What is a
Mitochondria?

Back 35

1. Site of cellular respiration where ATP is
generated by extracting energy from organic
compounds in the presence of oxygen
2. Often numbering in the thousands or hundreds
of thousands, depend ing upon cell activity
3. Found in most eukaryotic cells


4. Outer membrane is smooth, separating mitochondria from cytoplasm
5.Inner membrane is convoluted with foldings (cristae)
6.Matrix – compartment that contains many different enzymes, DNA, and ribosomes

Front 36

What is a
Chloroplasts?

Back 36

Site of photosynthesis where sunlight is converted into chemical energy (organic compounds) from carbon dioxide and water
2. Contain the green pigment chlorophyll
3.Found in leaves, other green organs of plants and algae

Front 37

What is a
Thylakoids?

Back 37

membranous system in the
form of flat-tened, interconnected disks

Front 38

What is a
Stroma?

Back 38

fluid outside of thylakoids which contains DNA, ribosomes, and many different enzymes

Front 39

What is a
Granum?

Back 39

stack of thylakoids

Front 40

What is the
Endosymbiosis of Mitochondria and Chloroplasts?

Back 40

1.Both organelles have a double membrane
2.Both organelles contain ribosomes
3.Both organelles contain circular DNA (prokaryotic)
4.Both organelles grow and reproduce independently of the cell

Front 41

What is a
Peroxisome?

Back 41

1.Specialized metabolic compartments surrounded by a single membrane; contain enzymes
2.Remove hydrogen atoms from various substrates and transfer them to oxygen (hydrogen peroxide - H2O2)
3.Also, breakdown fatty acids and detox alcohol and other toxic substances

Front 42

Cytoskeleton?

Back 42

1.Network of protein fibers extending throughout the cytoplasm
2.Provides mechanical shape and support to the cell
3.Provides anchorage for organelles and molecules
4.Promotes motility inside/outside the cell

Front 43

What is a
Microtubule?

Back 43

a)Maintains cell shape
b)Promotes organelle movement and chromosome movement during cell division (centrioles)
c)Promotes motility (cilia & flagella)

Front 44

What is a
Microfilaments ?

Back 44

a)Maintains and changes cell shape
b)Promotes muscle contraction and cytoplasmic streaming (animal and plant)
c)Initiates cell division (cleavage furrow - animal)
d)Promotes motility (pseudopodia - animal)

Front 45

What is a
Intermediate filaments?

Back 45

a)Maintains cell shape
b)Anchors nucleus and other organelles
c)Forms nuclear lamina

Front 46

What is a Centrome?

Back 46

structure present in cytoplasm of ani-mal cells that functions as a microtubule-organizing center and is important during cell division (has two centrioles)

Front 47

What is a
Centriole?

Back 47

structure in centrosome of animal cell, composed of a cylinder of microtubule triplets ar-ranged in a 9 + 0 pattern (occurs in pairs); respon-sible for spindle formation

Front 48

s
What is a
Cilia

Back 48

short appendages specialized for locomotion or moving fluid past the animal cell; composed of a cylinder of microtubule doublets arranged in a 9 + 2 pattern; shorter and numerous

Front 49

What is a
Flagella?

Back 49

long appendage specialized for locomotion in the animal cell; composed of a cylinder of micro-tubule doublets arranged in a 9 + 2 pattern; longer and singular

Front 50

What is Actin?

Back 50

globular protein that links into chains, two of which twist helically around each other; forming microfilaments in muscle (with myosin) and other kinds of cells

Front 51

What is
Cytoplasmic streaming?

Back 51

circular flow of cytoplasm involving interactions between actin and myosin filaments; speeds the distribution of materials with-in cells

Front 52

What is a
Pseudopodia?

Back 52

cellular extension of amoeboid cells used in moving and feeding, involving interactions between actin and myosin filaments

Front 53

What is a
Cell wall?

Back 53

protective layer external to the plasma membrane in the cells of plants and fungi; poly-saccharides such as cellulose (plants) and chitin (fungi) are important structural components of cell walls
a)Protects the cell while maintaining shape
b)Prevents excessive water uptake
c)Pectin glues adjacent cells together

Front 54

What is a
Extracellular matrix?

Back 54

meshwork surrounding animal cells, consisting of glycoproteins, polysaccharides, and proteoglycans synthesized and secreted by the cells; regulates cell behavior

Front 55

What is
Plasmodesmata?

Back 55

open channels through cell walls that connect the cytoplasm of adjacent plant cells allowing materials to pass between cells

Front 56

What are
Tight junctions?

Back 56

prevent leakage of material through spaces between cells

Front 57

What are
Desmosomes?

Back 57

function as rivets, fastening cells together

Front 58

What are
Gap junctions?

Back 58

consist of proteins surrounding a pore that allows the passage of materials between cells

Front 59

motor protein

Back 59

a protein that interacts with cytoskeletal elements and other cell components, producing movement of the whole cell or parts of the cell

Front 60

endomembrane system

Back 60

the collection of membranes inside and around a eukaryotic cell , related either through direct physical contact or by the transfer of membranous vesicles; includes the smooth and rough endoplasmic reticulum , the golgi apparatus , lysosomes, and vacuoles