Ultrastructure of the Cell 1.2

Question 1

State the function of an exocrine gland cell in the pancreas.

Answer 1

Exocrine gland cells synthesize molecules (often proteins) for secretion from the cell into an external space.

Exocrine gland cells of the pancreas secrete enzymes that function in digestion in the small intestine.

Question 2

Explain how an improvement in apparatus allowed for greater understanding of cell structure.

Answer 2

Technology = machinery and equipment developed from the application of scientific knowledge.

Begets = gives rise to; brings about.

Discovery = the act of finding or learning something for the first time.

Question 3

Define “resolution.”

Understanding: Electron microscopes have a much higher resolution than light microscopes.

Answer 3

The smallest interval distinguishable by the microscope, which then corresponds to the degree of detail visible in an image created by the instrument.

Question 4

Compare the functionality of light and electron microscopes.

Answer 4

LIGHT MICROSCOPES
Use lenses to bend light and magnify images.
Used to study dead or living cells in color.
Cell movement can be studied.
Larger field of view.
Objects can be magnified up to 2000X.
Can resolve objects 200 nm apart.

ELECTRON MICROSCOPES
Uses electron beams focused by electromagnets to magnify and resolve.
Requires cells to be killed and chemically treated before viewing.
No movement can be seen.
Without stain or dye, no color can be seen.
Smaller field of view.
Can magnify objects up to 250,000 times.
Can resolve objects that are 0.2 nm apart.

Question 5

Outline the major differences between prokaryotic and eukaryotic cells.

Answer 5

Prokaryotic Cells
Smaller (about 0.2 - 2 um)
DNA in nucleoid region (no nuclear membrane)
No membrane bound organelles
Cell wall of peptidoglycan
Smaller ribosomes (70s) in cytoplasm
DNA is circular and without histone proteins
Has plasmid DNA
Asexual cell division

Eukaryotic Cells
Bigger (10-100 um)
DNA in a true nucleus
Membrane bound organelles present
Cell wall of cellulose (plants) or chitin (fungus)
Larger ribosomes (80s) in cytoplasm and on ER
//also has 70s ribosomes within mitochondria and chloroplasts//
DNA is linear with histone proteins
Do not have plasmid DNA
Asexual or sexual cell division

Question 6

Cell Wall Function in Prokaryotic Cells:

Answer 6

All prokaryotic cells have a stiff cell wall, located underneath the capsule (if there is one). This structure maintains the cell’s shape, protects the cell interior, and prevents the cell from bursting when it takes up water.

Question 7

Plasma Membrane Function in Prokaryotic Cells:

Answer 7

It physically separates the cytoplasm from the outside environment. The plasma membrane also works as a selectively permeable, or semipermeable, barrier that controls what enters and exits the cell.

Question 8

Cytoplasm Function in Prokaryotic Cells:

Answer 8

The cytoplasm is the gel-like fluid inside the cell. It is the medium for chemical reaction. It provides a platform upon which other organelles can operate within the cell. All of the functions for cell expansion, growth and replication are carried out in the cytoplasm of a cell.

Question 9

Pili Function in Prokaryotic Cells:

Answer 9

Helps Transformation of DNA between 2 cells.

Question 10

70S Ribosomes Function in Prokaryotic Cells:

Answer 10

Site for Protein Synthesis

Question 11

State the function of the prokaryotic cell flagella.

Answer 11

Found in some (not all) prokaryotic cells.

Long extension used for cell locomotion.

Question 12

Explain why understanding of the ultrastructure of prokaryotic cells must be based on electron micrographs.

Answer 12

“Ultrastructures” are small structures of/in a biological specimen that are too little to see with a light microscope.

Question 13

Define “asexual reproduction.”

Answer 13

Asexual reproduction creates offspring from a single parent organism.

The offspring are genetic clones of that parent.

Question 14

Outline the four steps of binary fission.

Answer 14

1. The nucleoid DNA replicates to create an exact duplicate copy.
2. The nucleoid DNAs attach to the cell membrane.
3. The cell membrane (and wall, if present) grow, causing the cell to elongate and the DNA molecules to move apart from each other.
4. The cell membrane pinches inward, creating two genetically identical cells.

Question 15

State the meaning and advantages of eukaryotic cells being “compartmentalized.”

Answer 15

Compartmentalization is the presence of membrane bound partitions (organelles) within the eukaryotic cell. The compartments allow for:

1. Specialization of regions within the cell for specific functions.
2. Molecules needed for a specific function to be concentrated in a region within the cell.

Question 16

State structural differences between plant and animal cells.

Answer 16

Animal Cells
No cell wall
No chloroplasts
No large vacuole
Not a fixed shape
Stores carbohydrates as glycogen

Plant Cells
Cell wall
Chloroplasts
Large vacuole
Fixed shape
Stores carbohydrates as starch

Question 17

Draw and label a diagram of the ultrastructure of a generic animal cell.

Answer 17

Cell membrane shown as a single continuous line

Nucleus drawn with double membrane and nuclear pores

Mitochondria with a double membrane, the inner one folded into internal projections, shown no larger than half the nucleus

Rough endoplasmic reticulum drawn as a multi-folded membrane with dots on surface

Golgi apparatus drawn as a series of enclosed sacs with evidence of vesicle formation

80S ribosomes drawn as small discrete dots (not circles) in cytoplasm and on rER

lysosome and vesicles drawn as circles with single line

Question 18

State the function of an exocrine gland cell in the pancreas.

Answer 18

Exocrine gland cells synthesize molecules (often proteins) for secretion from the cell into an external space.

Exocrine gland cells of the pancreas secrete enzymes that function in digestion in the small intestine.

Question 19

Describe the function of the plasma membrane in an exocrine gland cell.

Answer 19

Forms the boundary of the cell, acts as a selective barrier allowing certain materials to pass into and out of the cell.

Question 20

Describe the function of the nucleus in an exocrine gland cell.

Answer 20

Contains most of the genes that control the eukaryotic cell, contains the nucleolus and chromatin.

Question 21

Describe the function of the mitochondria in an exocrine gland cell.

Answer 21

The location of aerobic cellular respiration used to make ATP.

Question 22

Describe the function of the Golgi apparatus in an exocrine gland cell.

Answer 22

Consists of flattened membranous sacs; receives transport vesicles from the ER,
modifies proteins produced in the ER, produces secretory vesicles

Question 23

Describe the function of the lysosomes in an exocrine gland cell.

Answer 23

Contains digestive enzymes that are used to break apart cellular debris and waste.

Question 24

Describe the function of the vesicles in an exocrine gland cell.

Answer 24

Transport materials within the cell and out of the cell via exocytosis.

Question 25

Describe the function of the endoplasmic reticulum in an exocrine gland cell.

Answer 25

Ribosomes on the ER synthesize proteins which are then moved through the ER and packaged into vesicles for transport.

Question 26

Identify the nucleus in a micrograph of a eukaryotic cell.

Answer 26

Often stained a darker color, look for a nuclear membrane and the nucleolus.

Question 27

Identify the Golgi apparatus in a micrograph of a eukaryotic cell.

Answer 27

Look for stacks of lines, without little dark dots attached. Typically further from the nucleus than ER.

Question 28

Identify the lysosome in a micrograph of a eukaryotic cell.

Answer 28

Little sacs, often a light grey color. Hard to distinguish from vesicles.

Question 29

Identify the vacuole in a micrograph of a eukaryotic cell.

Answer 29

Clear sac, typically larger in size than a vesicle or lysosome. More prevalent in plant cells than in animal cells.

Question 30

Identify the flagella in a micrograph of a eukaryotic cell.

Answer 30

Long tail-like structure emerging from the main cell body.

Question 31

Identify the cell wall in a micrograph of a eukaryotic cell.

Answer 31

Rigid outermost layer of a plant cell, external to the cell membrane. Thicker than the cell membrane.

Question 32

State the function of the prokaryotic cell capsule.

Answer 32

Found in some (not all) prokaryotic cells. Helps the cell maintain moisture and adhere to surfaces. Protects the cells from other organisms.

Question 33

Contrast the size of eukaryotic and prokaryotic ribosomes.

Answer 33

Prokaryotes have a smaller, 70s ribosome. Eukaryotes have a larger, 80s ribosome. Although, the mitochondria and chloroplasts within eukaryotic cells have 70s ribosomes. (The "s" stands for Svedberg unit, a measure of particle sedimentation rate)

Question 34

Draw the ultrastructure of E.coli, including the cell wall, pili, flagella, plasma membrane, cytoplasm, 70s ribosomes, and nucleoid with naked DNA.

Answer 34

Cell wall drawn uniformly thick and outside the cell membrane Capsule drawn outside the cell wall Pili drawn as hair-like structures connected to cell wall Flagellum drawn at one end only and longer than pili Cell membrane represented by a continuous single line 70S ribosomes drawn as small discrete dots (not circles) Nucleoid DNA shown as a tangled line not enclosed in membrane Plasmid drawn as a small circular ring of DNA Cytoplasm labeled within the cell

Question 35

Draw and label a diagram of the ultrastructure of a generic plant cell.

Answer 35

Cell wall drawn on outside perimeter with two continuous lines to indicate the thickness Cell membrane shown as a single continuous line Nucleus drawn with double membrane and nuclear pores Vacuole drawn with a single continuous line Chloroplast drawn with a double line and internal stacks of thylakoid Mitochondria with a double membrane, the inner one folded into internal projections, shown no larger than half the nucleus 80S ribosomes drawn as small discrete dots (not circles) in the cytoplasm and on rER

Question 36

Explain why cells with different functions will have different structures.

Answer 36

Cells will have different types and/or quantities of organelles depending on the primary function of the cell type. This allows for cells to specialize for a specific task.

Question 37

Prokaryotes

Answer 37

Prokaryotes are organisms whose cells lack a nucleus and other organelles. Prokaryotes are divided into two distinct groups: the bacteria and the archaea, which scientists believe have unique evolutionary lineages. Most prokaryotes are small, single-celled organisms that have a relatively simple structure.

Question 38

Eukaryotes

Answer 38

Eukaryotes are organisms whose cells have a nucleus;. All animals, plants, fungi, and many unicellular organisms, are Eukaryotes

Question 39

Mitosis

Answer 39

Prophase – The chromosomes shorten and thicken. Metaphase – Chromosomes line up in the middle of the cell. Anaphase – Chromatids break apart at the centromere and move to opposite poles. Telophase – Two nuclei formed after nuclear envelopes reform around each group of chromosomes.

Question 40

Function of Nucleoid in Prokaryotic Cells

Answer 40

DNA with ends that come together to form a circle and is NOT wrapped around proteins (termed “naked”)

Question 41

Define Extracellular

Answer 41

Extracellular means outside of the cell. Any structure outside of the cell membrane is considered extracellular: Cell wall Pili Capsule Flagellum

Question 42

What Ribosomes are in Eukaryotes and Prokaryotes?

Answer 42

Prokaryotes have a smaller (70s) ribosomes. Eukaryotes have a larger (80s) ribosomes.

Question 43

What is Cell Compartmentalization?

Answer 43

Cell compartmentalization basically refers to the way organelles present in the eukaryotic cells live and work in separate areas within the cell in order to perform their specific functions more efficiently.

Question 44

Define Micrograph: (Light and Electron), Which has higher magnification and resolution?

Answer 44

A micrograph is a photograph taken through a microscope. A “light micrograph” is a photo taken through a light microscope An “electron micrograph” is a photo captured through an electron microscope. Remember, electron microscopes have a much higher magnification and resolution than light microscopes

Question 45

Function of Plasma Membrane in Eukaryotic Cells

Answer 45

Controls movement of substances in and out of cell

Question 46

Function of Cystoplasm in Eukaryotic Cells

Answer 46

Fills the cell and holds organelle. Contains enzymes that catalyse reactions

Question 47

Function of Mitochondria in Eukaryotic Cells

Answer 47

A site of cellular respiration which ATP is generated

Question 48

Function of 80S Ribosomes in Eukaryotic Cells

Answer 48

Site of Protein Synthesis

Question 49

Function of Nucleus in Eukaryotic Cells

Answer 49

Controls all activities of cell and reproduction of unicellular organisms

Question 50

Function of Nucleolus in Eukaryotic Cells

Answer 50

Part of nucleus which is involved in production of ribosomes

Question 51

Function of sER in Eukaryotic Cells

Answer 51

Producing and storing lipids, including steroids

Question 52

Function of rER in Eukaryotic Cells

Answer 52

Synthesizes protein for secretion (preparation to exit the cell) from the cell

Question 53

Function of Golgi Apparatus in Eukaryotic Cells

Answer 53

Processes protein brought in vesicles from rER

Question 54

Function of Vesicles in Eukaryotic Cells

Answer 54

A small sac that transports and releases substance from the cell

Question 55

Function of Lysosomes in Eukaryotic Cells (only animal cell)

Answer 55

High concentration fo protein Destruction of microbes Destruction of old cellular organelles

Question 56

Function of Centrioles in Eukaryotic Cells (only animal cell)

Answer 56

Important role in nuclear division by establishing microtubules (components of cytoskeleton)

Question 57

Function of Vacuole in Eukaryotic Cells

Answer 57

Osmotic balance of cell and storage of substances

Question 58

Function of Cell Wall in Eukaryotic Cells (only plant)

Answer 58

Protects cell and keeps shape

Question 59

Function of Chloroplast in Eukaryotic Cells (only plant)

Answer 59

Responsible for photosynthesis which can produce energy

Question 60

Osmosis

Answer 60

spontaneous passage or diffusion of water or other solvents through a semipermeable membrane

Question 61

Leaf palisade mesophyll cell

Answer 61

The palisade mesophyll layer is where most of the photosynthesis occurs in the leaf.

Question 62

Cillia

Answer 62

Microtubule-based hair-like organelles extend from the surface of almost all cell types of the human body.

Question 63

Cell Wall

Answer 63

Encloses cell, maintains shape, prevents bursting in hypertonic media

Question 64

Plasma Membrane

Answer 64

Controls movement of substances in and out of the cell

Question 65

Cytoplasm

Answer 65

Fills the cell and is responsible for metabolic reactions

Question 66

Pili

Answer 66

Protein filaments on the cell wall | helps with DNA transferring between two cells

Question 67

Flagella

Answer 67

Longer then the pili, responsible for locomotion,

Question 68

70S Ribosomes

Answer 68

Site for protein synthesis

Question 69

Nucleoid Region (Prokaryote)

Answer 69

Controls activities of the cell and reproduction of the organism

Question 69

Nucleoid Region (Prokaryote)

Answer 69

Controls activities of the cell and reproduction of the organism

Question 70

Plasmids

Answer 70

Small Circles of DNA that carry some genes, they give antibiotic resistance

Question 71

Mitochondria

Answer 71

Responsible for Cellular Respiration where ATP is generated

Question 72

sER

Answer 72

Producing and storing lipids like steroids

Question 73

rER

Answer 73

Transports the protein produced by ribosomes on its surface to Golgi apparatus

Question 74

Vesicles

Answer 74

Small sac that transports and releases substances by the cell - fuses with cell membrane

Question 75

Lysosomes (Not in plant cells)

Answer 75

Responsible for the Destruction of microbes engulfed by white blood cells

Question 76

Centrioles (Not in plant cells)

Answer 76

Helps with the process of nuclear division by helping to establish microtubules.

Question 77

Vacuole

Answer 77

Helps with osmotic balance of the cell and storage of substances

Question 78

Chloroplast

Answer 78

Responsible for protein synthesis

Question 79

Interphase

Answer 79

DNA Copied

Question 80

Prophase

Answer 80

Chromosomes Paired

Question 81

Metaphase

Answer 81

Chromosomes lined at the equator

Question 82

Anaphase

Answer 82

Sister Chromatids Pulled

Question 83

Telophase

Answer 83

Cell pinches in middle

Question 84

Cytokinesis

Answer 84

Identical Daughter Cells

Question 85

Compartmentalization

Answer 85

seen in eukaryotes; the consequence of organelles being membrane-bound.

Question 86

Palisade mesophyll

Answer 86

photosynthetic tissue below the epidermis in a leaf.

Question 87

Transmission electron microscope

Answer 87

an electron microscope that produces two-dimensional images.

Question 88

Resolution

Answer 88

the ability to see adjacent objects or structures as distinct from each other.

Question 89

E. coli (as a representative prokaryotic cell)

Answer 89

Escherichia coli, a prokaryote, is widely used as research material.