Biology Flashcards
are the basic building blocks of all living things.
Cells
Hooke detailed his observations of
this tiny and previously unseen world in his book,
Micrographia.
improved the design of the existing compound microscope in 1665.
Robert Hooke
published
his observations on tiny living
organisms which he named
animalcules.
Antonie van Leeuwenhoek
was the first to observe
under his microscope the structure of
a red blood cell of different animals as
well as a sperm cell.
Antonie van Leeuwenhoek
He markedly indicated
that inside the cell is a dark dense spot which he termed
as the nucleus.
Robert Brown
concluded that all plant parts are made of cells.
Matthias Schleiden
stated that all animal tissues are composed
of cells, too.
Theodor Schwann
Rudolph
Virchow’s powerful dictum,
Omnis cellula e cellula, “All cells only arise from
preexisting cells”.
Cell theory
(1) all living things are composed of one or more cells;
(2) the cell is the basic unit of life; and (3) all cells arise from preexisting cells.
A cell consists of three parts:
the cell membrane, the nucleus, and, between the two,
the cytoplasm.
DNA synthesis; RNA synthesis; assembly of ribosomes
Nucleus
Responsible for Protein synthesis
Ribosomes
Synthesis of membrane lipids and proteins, secretory proteins,
and hydrolytic enzymes; formation of transport vesicles
Rough ER
Lipid synthesis; detoxification in liver cells
Smooth ER
Modification and transport of macromolecules; formation of
lysosomes and transport vesicles
Golgi apparatus
Digestion of ingested food, bacteria, and a cell’s damaged
organelles and macromolecules for recycling
Lysosomes
Digestion; storage of chemicals; cell enlargement; water balance
Vacuoles
Diverse metabolic processes, with breakdown of
H2O2 by – product
Peroxisomes
Conversion of chemical energy of food to chemical energy of
ATP
Mitochondria
Conversion of light energy to chemical energy of sugars
Chloroplasts
Jelly – like substance that holds the cell organelles in place; site of many chemical reactions
Cytoplasm
Structural support; movement; road for transportation
Cytoskeleton
Helpers in cell division
Centrioles
Separates cell from outside; controls what enters and leaves
the cell; recognizes signals from other cells
Cell membrane
Nonliving permeable wall that surrounds the cell membrane;
encloses and supports the cell
Cell wall
Provides instruction for the cells activities, (growth,
reproduction)
Chromatin
are made up of a group of similar cells that are adapted for a particular
function.
Tissues
Plant tissues can be broadly
categorized into
dividing, meristematic tissue or non-dividing, permanent tissue.
Permanent tissue is made up of
simple and complex tissues
is found in buds and growing
tips of plants. It generally makes plants grow taller or longer.
Apical meristematic tissue
makes the plant grow thicker.
Lateral meristematic tissue
The
process of developing a particular structure suited to a specific function is known as
cellular differentiation.
Simple permanent tissues
Simple permanent tissues
* Epidermis
* Parenchyma
* Collenchyma
* Sclerenchyma
Complex permanent tissues
Complex permanent tissues
* xylem vessels (made up of tracheids and vessels)
* phloem vessels (made up of sieve tubes and companion cells)
is a single layer of cells that covers plants’ leaves, flowers, roots and
stems. It is the outermost cell layer of the plant body and plays a protective role in the plant.
epidermis tissue
is a pore found in the leaf and stem
epidermis that allows for gaseous exchange.
stoma
are bean shaped specialized epidermal
cells, found mainly on the lower surface of
leaves, which are responsible for regulating the
size of the stoma opening.
guard cells.
Together, the stoma
and the guard cells are referred to as
stomata.
are located
in the region between epidermal and vascular
tissue.
ground tissues
forms the majority of stems and roots as well as soft fruit like tomatoes
and grapes. It is the most common type of ground tissue.
Parenchyma tissue
is responsible
for the storage of nutrients.
Parenchyma tissue
is a simple, permanent tissue typically found in the shoots and leaves
of plants.
Collenchyma tissue
is a simple, permanent tissue. It is the supporting tissue in plants,
making the plants hard and stiff.
Sclerenchyma tissue
Two types of sclerenchyma cells exist:
fibers and
sclereids.
are long and narrow and have thick lignified cell walls. They provide
mechanical strength to the plant and allow for the conduction of water.
Sclerenchyma fibers
are specialized sclerenchyma cells with thickened, highly lignified walls with pits
running through the walls. They support the soft tissues of pears and guavas and are found
in the shells of some nuts.
Sclereids
Forms the outer layers of the body and also lines many of the bodies cavities where it has a protective function.
Eptithelial tissue
assists in support and protection of organs and limbs and depending on the location in the body it may or separate organs or parts of the body
Connective tissue
Enables various forms of movement, both voluntary and involuntary
muscle tissue
is responsible for the carrying of electrical and chemical signals and impulses from the brain and central nervous system to the periphery, and vice versa.
nerve tissue
serve as barriers for pathogens, mechanical injuries, and fluid loss. establishing a barrier between different compartments of the body,
tight junctions
for secretion
cuboidal
brick-shaped cells; for secretion and active absorption
simple columnar
squamous—plate-like cells; for exchange of material through diffusion
simple squamous
multilayered and regenerates quickly; for protection
stratified squamous
single layer of cells; may just look stacked because of varying
height; for lining of respiratory tract; usually lined with cilia
pseudo-stratified columnar
These tissues are composed of long cells called muscle fibers that allow
the body to move voluntary or involuntary.
Muscle Tissue
striated; voluntary movements
skeletal muscle tissue
not stiriated
smooth tisue
a long and narrow protrusion. It absorbs water and mineral salts by osmosis and active
transport respectively.
root hair cell
are finger-like projections that arise from the epithelial layer in some
organs. They help to increase surface area allowing for faster and more efficient adsorption
Microvilli
is made up of long cells joined end to end. It transports water and
minerals from the roots to other parts of a plant as well as to provide support to the whole
plant hence enable a plant to stand erect.
Xylem vessel
are cells in between a stoma. It helps the guard cells to bend outward
when they become turgid.
Guard cells
is generally elongated and elastic containing mitochondria in large number.
Muscle
cell
DNA replication and cell growth also take place.
CELL CYCLE
represents the phase when the actual cell division or mitosis occurs
M phase
represents the phase between two successive M phases.
Interphase
The interphase is divided into three further phases:
G1 phase (Gap 1) * S phase (Synthesis) * G2 phase (Gap 2)
corresponds to the interval between mitosis and initiation of DNA
replication.
G1 phase
the cell is metabolically active and continuously
grows but does not replicate its DNA.
G1 phase
marks the period during which DNA synthesis or
replication takes place.
S or synthesis phase
proteins are synthesised in preparation for mitosis
while cell growth continues.
G2 phase
cells that do not divide further exit
G1 phase to enter an inactive stage called
quiescent stage (G0)
Nuclear division is also called
karyokinesis
