Week 2 Lecture: Plant Cell Structures

Question 1

It is commonly known as lentil, an edible legume. It is also an annual plant known for its lens-shaped seeds.

Answer 1

Vicia lens or Lens culinaris

Question 2

A book by Robert Hooke published in ___ that inspired a wide public interest in the new science of microscopy.

Answer 2

January 1665, Micrographia

Question 3

This book originated the biological term cell.

Answer 3

Micrographia

Question 4

Using single-lensed microscopes of his own design and make, he was the first to observe and to experiment with microbe.

Answer 4

Antonie Philips van Leeuwenhoek

Question 5

He improved lenses creating microscopes that established microbiology.

Answer 5

Antonie Philips van Leeuwenhoek

Question 6

Antonie Philips van Leeuwenhoek worked on a variety of microscopic specimens from ___.

Answer 6

animal, plant and fungal tissues, bacteria and protozoa

Question 7

It is the fundamental scientific theory of biology, stating that cells are the basic units of all living tissues.

Answer 7

Cell Theory

Question 8

Cell Theory was first proposed in ___ by German scientists ___ and ___

Answer 8

1838, Theodor Schwann and Matthias Jakob Schleiden

Question 9

These are Plant Life Unifying Principles:

Answer 9

1. Earth’s primary producers, solar harvesters, light energy converters (be it a bryophyte, fern, gymnosperm or angiosperm)
2. Other than certain reproductive cells, they are non-motile. They grow toward essential resources.
3. Structurally reinforced to grow towards sunlight and against gravity.
4. Lose water continuously and evolved mechanisms to avoid dessication.
5. Have mechanisms to move water and minerals to sites of photosynthesis and growth, and also to move the products of photosynthesis to non-photosynthetic organs and tissues.

Question 9

In ___, ___, proposed ___ (“all cells (come) from cells or generated by existing cells).

Answer 9

1855, Rudof Virchow, Omnis cellula e cellula

Question 10

New cells are produced by dividing tissues called ___.

Answer 10

meristems

Question 11

Each plant cell is surrounded by a rigid cellulosic ___ and each walled cell is cemented together by a ___.

Answer 11

cell wall, middle lamella

Question 12

Determines the mechanical strength of plant structures, allows vertical growth.

Answer 12

Cell wall

Question 13

Glue cells together, preventing sliding past one another and acts as cellular “exoskeleton” controlling cell shape

Answer 13

Cell wall

Question 14

Allows high turgor pressures to develop and determines cell turgor pressure and cell volume.

Answer 14

Cell wall

Question 15

Allows bulk flow of water in xylem requiring a mechanically tough wall that resists collapse as there is negative pressure in the xylem.

Answer 15

Cell wall

Question 16

It is thin composed of rigid cellulose microfibrils embedded in a matrix of polysaccharides called hemicelluloses (flexible) and gel-forming pectin with a small amount of structural protein.

Answer 16

Primary cell wall

Question 16

Major structural barrier to pathogen invasion.

Answer 16

Cell wall

Question 17

The primary cell wall is composed of rigid ___ embedded in a matrix of polysaccharides called ___ (flexible) and gel-forming ___ with a small amount of ___.

Answer 17

cellulose microfibrils, hemicelluloses, pectin, structural protein.

Question 18

It forms when primary wall expansion stops; thick as in tracheids, fibers and others that serve in mechanical support.

Answer 18

Secondary cell wall

Question 19

The secondary cell wall is composed of ___ that bonds tightly to ___; reduces digestibility of plant material by animals and attack by pathogen.

Answer 19

lignin, cellulose

Question 20

According to ___, all biological membranes have the same basic molecular organization: - in the case of plasma membranes, a bilayer of ___ and various ___ with ___ and ___.

Answer 20

Fluid-Mosaic Model, phospholipids, transport proteins, chloroplasts, glycosylglycerides

Question 21

___ is strongly influenced by temperature

Answer 21

Membrane fluidity

Question 22

Generally, plants cannot ___ body temperature.

Answer 22

generate

Question 23

Membrane fluidity ___ as temperature decreases. To avoid this, one of the fatty acids of phospholipids is ___ (no double bond), the other is ___ because of the cis double bonds that prevents tight packing of phospholipids.

Answer 23

decreases, saturated, unsaturated

Question 24

Transport Proteins in Membrane Lipid Bilayer are:

Answer 24

1. Integral Proteins 2. Peripheral Proteins 3. Anchored Proteins

Question 25

Embedded in the lipid bilayer, serve as *ion channels.*

Answer 25

Integral Proteins

Question 25

Bound to the membrane surface by *noncovalent bonds* and could be disassociated, ex. microtubules and microfilaments

Answer 25

Peripheral Proteins

Question 26

Bound to the membrane *via lipid molecules* like fatty acids.

Answer 26

Anchored Proteins

Question 27

Contains most genetic material of the cell (the remainder of the genetic information of the cell is contained in the chloroplast and mitochondrion

Answer 27

Nucleus

Question 28

Which parts of the cell contains the remainder of the genetic information that is not in the nucleus?

Answer 28

Chloroplast and mitochondrion

Question 29

The nucleus is surrounded by a ___ with ___.

Answer 29

nuclear envelope, nuclear pores

Question 30

This chromatin when it forms a solid-like cylinder containing 8 histones forms a __

Answer 30

Nucleosome

Question 31

It is the DNA-protein complex.

Answer 31

Chromatin

Question 32

The nucleus also consists of a densely granular region which is the site of ribosome synthesis, called the ___.

Answer 32

Nucleolus

Question 33

The endoplasmic reticulum is ___ to the outer membrane of the nucleus.

Answer 33

continuous

Question 33

*Network of internal membranes* made of lipid bilayers and associated proteins, together form flattened or tubular sacs known as cisternae.

Answer 33

Endoplasmic Reticulum

Question 34

Site of *synthesis of membrane proteins* and also proteins secreted outside of the cell or into the vacuoles.

Answer 34

Rough ER

Question 34

Proteins and polysaccharides for secretion are processed.

Answer 34

Golgi apparatus

Question 35

Site of *lipid synthesis* and membrane assembly.

Answer 35

Smooth ER

Question 36

The golgi apparatus consist of one or more stacks of three to ten flattened membrane sacs or ___, and an irregular network of tubules and vesicles called the ___.

Answer 36

cisternae, trans Golgi Network (TGN)

Question 37

Each individual stack in a golgi apparatus is called a ___ or ___.

Answer 37

golgi body, dictyosome

Question 38

___ carry the polysaccharadies and glycoproteins to the plasma membrane by fusion and emptying their contents to the cell wall; some participate in endocytosis, the process that brings soluble and membrane-bound proteins into the cell.

Answer 38

Secretory vesicles

Question 38

The process that brings soluble and membrane-bound proteins into the cell.

Answer 38

Endocytosis

Question 39

It is *surrounded by a vacuolar membrane* or tonoplas.

Answer 39

Large central vacuole

Question 40

Like animal lysosomes, plant vacuoles contain ___.

Answer 40

hydrolytic enzymes

Question 40

Contains water and dissolved inorganic ions, organic acids, sugars, enzymes and a variety of secondary metabolites.

Answer 40

Large central vacuole

Question 41

Cellular site of respiration

Answer 41

Mitochondria

Question 41

These are specialized *protein-storing vacuoles* abundant in seeds.

Answer 41

Protein bodies

Question 42

The *membranes of chloroplasts* are known as ___, and a stack of it is a ___.

Answer 42

thylakoids, granum

Question 43

The mitochondria, from spherical to tubular, with smooth outer membrane and convoluted inner membrane called ___, and the compartment enclosed by cristae is the mitochondrial matrix containing the enzymes needed for Krebs Cycle

Answer 43

cristae

Question 44

___ belong to a group called plastids that contain chlorophyll.

Answer 44

Chloroplasts

Question 45

Embedded in the thylakoid are ___ and other ___.

Answer 45

proteins, pigments

Question 46

The *fluid compartment* surrounding the thylakoid is the ___ which is analogous to the mitochondrial matrix

Answer 46

stoma

Question 47

These are other plastids:

Answer 47

1. Chromoplasts (with carotenoids) 2. Leucoplasts (nonpigmented) 3. Amyloplasts (starch-storing plastid)

Question 48

Mitochondria and chloroplasts both contain ___ to synthesize protein.

Answer 48

DNA and machinery

Question 49

Believed to have evolved from endosymbiotic bacteria

Answer 49

Mitochondria and chloroplasts

Question 50

The semi-autonomous organelles in plants are believed to have evolved from endosymbiotic bacteria. A. They divide by ___ b. They have circular chromosomes instead of linear which are located in mitochondrial matrix or plastid stroma called ___.

Answer 50

fission, nucleiods

Question 51

Although semi-autonomous plants organelles have their own genomes and can divide independently, however, majority of the proteins of these organelles still depend on the ___ hence the word ___.

Answer 51

nucleus, semi-autonomous

Question 52

*Found in meristem cells* with few or no internal membranes, no chlorophyll, and incomplete enzymes to carry out photosynthesis

Answer 52

Interconvertible Plastids

Question 53

Chloroplast development from proplastids are triggered by ___.

Answer 53

light

Question 54

Upon illumination, enzymes are formed inside the proplastid or imported from the cytosol producing light-absorbing pigments. Hence, chloroplasts develop only when a young shoot is exposed to ___.

Answer 54

light

Question 55

Chloroplasts can be converted to ___. Amyloplasts can be converted to ___.

Answer 55

chromoplasts, chloroplast

Question 56

Proplastids differentiate into ___ when seeds are germinated in the dark (if not in the soil) but after minutes of exposure to light, chlorophyll is produced which is derived from the protochlorophyll found in etioplasts; this can be reverted and the process is known as ___.

Answer 56

etioplasts, etiolation

Question 57

___ are single-membrane spherical organelles like: ___, which function in the *removal of H2* from organic substrates

Answer 57

Microbodies, peroxisomes

Question 58

Peroxisomes function in the removal of H2 from organic substrates: RH2 + O2 and R + H2O2 Where R is the organic substrate. This produces a ___ which is broken in peroxisomes by __.

Answer 58

harmful peroxide, catalase

Question 59

Glyoxysomes and Oleosomes/Spherosomes/Lipid bodies are examples of ___.

Answer 59

microbodies

Question 60

*Present in all oil-storing seeds* which contain enzymes that convert stored fatty acids into sugars (glyoxylate cycle).

Answer 60

Glyoxysomes

Question 61

Lipids from ___ are broken down and converted to sucrose with the help of ___.

Answer 61

oleosomes, glyoxysomes

Question 61

During seed development, *triacylglycerol* in the form of oil is stored in these *bodies*.

Answer 61

Oleosomes/Spherosomes/Lipid bodies

Question 62

The __ of a plant cell is *organized by a 3- dimensional network* of filamentous proteins which provides spatial organization of the organelles.

Answer 62

cytosol

Question 63

Serves as a *scaffolding* for the movement of organelles and other cytoskeletal components.

Answer 63

Cytoskeleton

Question 64

3 cytoskeletal types found in plants:

Answer 64

1. Microtubles 2. Microfilaments 3. Intermediate filaments

Question 65

__ are hollow cylinders with an *outer dia.of 25 nm*, composed of protein tubulin

Answer 65

Microtubules

Question 66

___ are solid with a dia.of 7 nm, composed of globular actin or G-actin

Answer 66

Microfilaments

Question 67

__ are helically wound fibrous elements with *10 nm dia.* composed of linear polypeptide monomers

Answer 67

Intermediate filaments,

Question 68

It is an integral part of mitosis.

Answer 68

Microtubules

Question 69

Form the ___, a ring of microtubules encircling the nucleus before the start of prophase

Answer 69

Preprophase Band (PPB)

Question 70

Form the ___ (during prophase, analogous to centrosomes of animal cells) and ___ (during metaphase)

Answer 70

prophase spindle, mitotic spindle

Question 71

Along with ER, forms ___ (during late anaphase or early telophase)

Answer 71

phragmoplast

Question 72

__ *guides in cytoplasmic streaming* (a coordinated movement of particles and organelles in the cytosol) involving actin and myosin proteins.

Answer 72

Microfilaments

Question 73

*Guides vesicles of Golgi bodies* with wall precursors which fuses to the plasma membrane which are deposited and assembled as cell wall material.

Answer 73

Microfilaments

Question 74

___ traverse cell walls connecting cytoplasms of adjacent cells, and because of this interconnection, a continuum is form known as the ___.

Answer 74

Plasmodesmata, symplast

Question 75

Tubular extensions of the plasma membrane

Answer 75

Plasmodesmata