Week 2 Lecture: Plant Cell Structures Flashcards
It is commonly known as lentil, an edible legume. It is also an annual plant known for its lens-shaped seeds.
Vicia lens or Lens culinaris
A book by Robert Hooke published in ___ that inspired a wide public interest in the new science of microscopy.
January 1665, Micrographia
This book originated the biological term cell.
Micrographia
Using single-lensed microscopes of his own design and make, he was the first to observe and to experiment with microbe.
Antonie Philips van Leeuwenhoek
He improved lenses creating microscopes that established microbiology.
Antonie Philips van Leeuwenhoek
Antonie Philips van Leeuwenhoek worked on a variety of microscopic specimens from ___.
animal, plant and fungal tissues, bacteria and protozoa
It is the fundamental scientific theory of biology, stating that cells are the basic units of all living tissues.
Cell Theory
Cell Theory was first proposed in ___ by German scientists ___ and ___
1838, Theodor Schwann and Matthias Jakob Schleiden
These are Plant Life Unifying Principles:
- Earth’s primary producers, solar harvesters, light energy converters (be it a bryophyte, fern, gymnosperm or angiosperm)
- Other than certain reproductive cells, they are non-motile. They grow toward essential resources.
- Structurally reinforced to grow towards sunlight and against gravity.
- Lose water continuously and evolved mechanisms to avoid dessication.
- 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.
In ___, ___, proposed ___ (“all cells (come) from cells or generated by existing cells).
1855, Rudof Virchow, Omnis cellula e cellula
New cells are produced by dividing tissues called ___.
meristems
Each plant cell is surrounded by a rigid cellulosic ___ and each walled cell is cemented together by a ___.
cell wall, middle lamella
Determines the mechanical strength of plant structures, allows vertical growth.
Cell wall
Glue cells together, preventing sliding past one another and acts as cellular “exoskeleton” controlling cell shape
Cell wall
Allows high turgor pressures to develop and determines cell turgor pressure and cell volume.
Cell wall
Allows bulk flow of water in xylem requiring a mechanically tough wall that resists collapse as there is negative pressure in the xylem.
Cell wall
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.
Primary cell wall
Major structural barrier to pathogen invasion.
Cell wall
The primary cell wall is composed of rigid ___ embedded in a matrix of polysaccharides called ___ (flexible) and gel-forming ___ with a small amount of ___.
cellulose microfibrils, hemicelluloses, pectin, structural protein.
It forms when primary wall expansion stops; thick as in tracheids, fibers and others that serve in mechanical support.
Secondary cell wall
The secondary cell wall is composed of ___ that bonds tightly to ___; reduces digestibility of plant material by animals and attack by pathogen.
lignin, cellulose
According to ___, all biological membranes have the same basic molecular organization: - in the case of plasma membranes, a bilayer of ___ and various ___ with ___ and ___.
Fluid-Mosaic Model, phospholipids, transport proteins, chloroplasts, glycosylglycerides
___ is strongly influenced by temperature
Membrane fluidity
Generally, plants cannot ___ body temperature.
generate
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.
decreases, saturated, unsaturated
Transport Proteins in Membrane Lipid Bilayer are:
- Integral Proteins
- Peripheral Proteins
- Anchored Proteins
Embedded in the lipid bilayer, serve as ion channels.
Integral Proteins
Bound to the membrane surface by noncovalent bonds and could be disassociated, ex. microtubules and microfilaments
Peripheral Proteins
Bound to the membrane via lipid molecules like fatty acids.
Anchored Proteins
Contains most genetic material of the cell (the remainder of the genetic information of the cell is contained in the chloroplast and mitochondrion
Nucleus
Which parts of the cell contains the remainder of the genetic information that is not in the nucleus?
Chloroplast and mitochondrion
The nucleus is surrounded by a ___ with ___.
nuclear envelope, nuclear pores
This chromatin when it forms a solid-like cylinder containing 8 histones forms a __
Nucleosome
It is the DNA-protein complex.
Chromatin
The nucleus also consists of a densely granular region which is the site of ribosome synthesis, called the ___.
Nucleolus
The endoplasmic reticulum is ___ to the outer membrane of the nucleus.
continuous
Network of internal membranes made of lipid bilayers and associated proteins, together form flattened or tubular sacs known as cisternae.
Endoplasmic Reticulum
Site of synthesis of membrane proteins and also proteins secreted outside of the cell or into the vacuoles.
Rough ER
Proteins and polysaccharides for secretion are processed.
Golgi apparatus
Site of lipid synthesis and membrane assembly.
Smooth ER
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 ___.
cisternae, trans Golgi Network (TGN)
Each individual stack in a golgi apparatus is called a ___ or ___.
golgi body, dictyosome
___ 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.
Secretory vesicles
The process that brings soluble and membrane-bound proteins into the cell.
Endocytosis
It is surrounded by a vacuolar membrane or tonoplas.
Large central vacuole
Like animal lysosomes, plant vacuoles contain ___.
hydrolytic enzymes
Contains water and dissolved inorganic ions, organic acids, sugars, enzymes and a variety of secondary metabolites.
Large central vacuole
Cellular site of respiration
Mitochondria
These are specialized protein-storing vacuoles abundant in seeds.
Protein bodies
The membranes of chloroplasts are known as ___, and a stack of it is a ___.
thylakoids, granum
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
cristae
___ belong to a group called plastids that contain chlorophyll.
Chloroplasts
Embedded in the thylakoid are ___ and other ___.
proteins, pigments
The fluid compartment surrounding the thylakoid is the ___ which is analogous to the mitochondrial matrix
stoma
These are other plastids:
- Chromoplasts (with carotenoids)
- Leucoplasts (nonpigmented)
- Amyloplasts (starch-storing plastid)
Mitochondria and chloroplasts both contain ___ to synthesize protein.
DNA and machinery
Believed to have evolved from endosymbiotic bacteria
Mitochondria and chloroplasts
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 ___.
fission, nucleiods
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 ___.
nucleus, semi-autonomous
Found in meristem cells with few or no internal membranes, no chlorophyll, and incomplete enzymes to carry out photosynthesis
Interconvertible Plastids
Chloroplast development from proplastids are triggered by ___.
light
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 ___.
light
Chloroplasts can be converted to ___. Amyloplasts can be converted to ___.
chromoplasts, chloroplast
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 ___.
etioplasts, etiolation
___ are single-membrane spherical organelles like: ___, which function in the removal of H2 from organic substrates
Microbodies, peroxisomes
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 __.
harmful peroxide, catalase
Glyoxysomes and Oleosomes/Spherosomes/Lipid bodies are examples of ___.
microbodies
Present in all oil-storing seeds which contain enzymes that convert stored fatty acids into sugars (glyoxylate cycle).
Glyoxysomes
Lipids from ___ are broken down and converted to sucrose with the help of ___.
oleosomes, glyoxysomes
During seed development, triacylglycerol in the form of oil is stored in these bodies.
Oleosomes/Spherosomes/Lipid bodies
The __ of a plant cell is organized by a 3- dimensional network of filamentous proteins which provides spatial organization of the organelles.
cytosol
Serves as a scaffolding for the movement of organelles and other cytoskeletal components.
Cytoskeleton
3 cytoskeletal types found in plants:
- Microtubles
- Microfilaments
- Intermediate filaments
__ are hollow cylinders with an outer dia.of 25 nm, composed of protein tubulin
Microtubules
___ are solid with a dia.of 7 nm, composed of globular actin or G-actin
Microfilaments
__ are helically wound fibrous elements with 10 nm dia. composed of linear polypeptide monomers
Intermediate filaments,
It is an integral part of mitosis.
Microtubules
Form the ___, a ring of microtubules encircling the nucleus before the start of prophase
Preprophase Band (PPB)
Form the ___ (during prophase, analogous to centrosomes of animal cells) and ___ (during metaphase)
prophase spindle, mitotic spindle
Along with ER, forms ___ (during late anaphase or early telophase)
phragmoplast
__ guides in cytoplasmic streaming (a coordinated movement of particles and organelles in the cytosol) involving actin and myosin proteins.
Microfilaments
Guides vesicles of Golgi bodies with wall precursors which fuses to the plasma membrane which are deposited and assembled as cell wall material.
Microfilaments
___ traverse cell walls connecting cytoplasms of adjacent cells, and because of this interconnection, a continuum is form known as the ___.
Plasmodesmata, symplast
Tubular extensions of the plasma membrane
Plasmodesmata
