Lesson 3: Cell Structures and Functions Flashcards
is reflected in the different shape and sizes of cells
cellular diversity
what happens when the cell grows bigger?
its surface area becomes too small to maintain its life functions
two types of cells that differ in internal organizations:
- prokaryotic cells
- eukaryotic cells
lack a nuclear envelope and membrane-bound organelles
prokaryotic cells
e.g. bacterial cells
- are generally larger and have very distinct nuclei that are clearly surrounded by nuclear membranes
- they also have numerous membrane-bound organelles found in the cytoplasm
eukaryotic cells
e.g. protists, plants, fungi, animals
why is cell division in eukaryotic cells comparatively different from that of prokaryotic cells?
because of the intricate organization of the DNA in eukaryotic cells
is the most common type of cell division in eukaryotes
mitosis
type of cell division found in prokaryotes
binary fission
simpler compared to mitosis
why are secretory cells located in glands expected to have more ribosomes, Golgi bodies, and ER?
Because they work hard in secreting the materials that the cells need
prokaryotic cells
a sticky outer layer that provides protection
capsule
prokaryotic cells
a structure that confers rigidity and shape to the cell
cell wall
prokaryotic cells
a structure that serves as permeability barrier
plasma membrane
prokaryotic cells
a genetic material
plasmid
prokaryotic cells
a DNA-containing region within the cytoplasm
nucleoid
prokaryotic cells
region where chromosomes (DNA), ribosomes and various inclusions are found
cytoplasm
prokaryotic cells
the site where protein is synthesized
ribosome
prokaryotic cells
a hair-like appendage that functions in adhesion
pilus (plural,pili)
prokaryotic cells
facilitates movement of bacteria
flagellum
eukaryotic cells have three main parts:
- cell membrane
- cytoplasm
- nucleus
sometimes called the plasma membrane, it is the outemost covering of animal cells
cell membrane
describes the cell membrane as a phospholipid bilayer sandwiched by a coat of protein on either surface
Davson-Danielli model
- now the widely accepted model
- decribes the plasma membrane as a mosaic of of protein that are embedded or attached to a fluid bilayer of lipid
Singer-Nicolson model or fluid mosaic model
- it regulates the substances that enter and exit the cell
- serves as a solvent for integral membrane proteins that run across the lipid bilayer
cell membrane
- all the materials in the cell that surround the nucleus
- ground substance and the biggest part of the cell where organelles are found
cytoplasm
is a network of intercommunicating channels in the cytoplasm
endoplasmic reticulum (ER)
two types of ER:
- rough endoplasmic reticulum (RER)
- smooth endoplasmic reticulum (SER)
- plays a role in the production of protein
- there are ribosomes attached on its surface
rough ER
- plays a role in manufacture and metabolism of lipids
- is more tubular and non-granular structure due to absence of ribosomes
smooth ER
has a role in the biosynthesis of steroid hormones
- is composed of sets of cisternae and numerous vesicles
- processing, packaging and sorting of secretory materials
Golgi apparatus
fill in the blank
after protein is synthesized by the 1. ____, it passes into the channel of the 2. ________ and moves into the fluid-filled sacs of the 3._______
- ribosomes
- ER
- Golgi apparatus
contains enzymes that help in the chemical oxidation of food molecules and produces energy in the form of ATP
mitochondrion
plural, mitochondria
prominent parts of the mitochondrion
crista (plural, cristae) and matrix
are numerous folds of the inner membrane of the mitochondrion
cristae
is the space inside the inner membrane of the mitochondrion
matrix
why do liver cells have more mitochondria compared to skin cells?
because liver cells are active most of the time compared to skin cells which are less active
contain a number of enzymes for intracellular digestion
lysosomes
- contains around 40 kinds of enzymes that help digest food, disease-causing bacteria engulfed by wbc, and worn-out and broken parts of the cell
- large, dense granules with membranes
- these fuse with the cell membrane to secrete substances
secretory granules
store fatty acids and sterols
lipid droplets
what happens when lipid droplets are stained with osmium tetroxide?
they appear as black spherical bodies
are non-membraneous substances and structures suspended in the cytoplasm with varying funtions
cytoplasmic inclusions
- site where proteins are made
- most numerous of all cytoplasmic structures
ribosomes
proteins that will be exported outside of the cell are produce by?
bound ribosomes
ribosomes attached to the ER
proteins that are needed by the cell itself are produced by?
free ribosomes
float freely in the cytoplasm
what central role in cell division does the centriole play?
where it participates in the formation of the mitotic spindle
composed of nine groups of parallel subunits arranged in a longitudinal fashion
centriole
is a structure that helps cells maintain their shape and internal organization
note: not in the book
cytoskeleton
together they form the cytoskeleton:
microtubules and microfilaments
- composed of linear polymers of tubulin
- forms the spindle apparatus that appears in cell division
microtubules
support the cell to maintain its structure and shape as it provides resliency against forces that can altar the shape
microfilaments
are examples of microfilaments that aid in the movement of chromosomes during cell division
spindle fibers
abundant in liver cells, play an important role in the glucose cycle
glycogen granules
do not require staining by dyes because they already posses their own color
pigments
- site where nucleic acids are synthesized
- directs all the activities of the cell
- storage of heriditary factors
nucleus
the nucleus is the source of the molecule responsible for various cellular functions such as genetic coding and expression
ribonucleic acid (RNA)
two layered outer limit of the nucleus separating it from the cytoplasm
nuclear membrane
dense protein rich substance inside the the nucleus
nucleoplasm
- it is suspended in the nucleoplasm
- resposible for ribosome formation
nucleolus
familiarize only:
what is being transcribed and assembled in the nucleoulus?
rRNA
act as selective channels between the cytoplasm and the inside of the nucleus, selectively allowing molecules which contain the correct localization signal to pass in and out
nuclear pores
can be seen in the nuclear envelope
made up of DNA and proteins and forms chromosomes during cell division
chromatin
found inside the nucleus
contain the genes inherited by the offspring from their parents
chromosomes
structures that are found in plant cells only:
- cell wall
- water vacuoles
- plastids
outermost rigid covering of plant cells
cell wall
provide strength and rigidity to the cell
the cell wall is primarily composed of?
cellulose
two types of cell walls
primary and secondary wall
with a lamella sandwiched in between - middle lamella
is the first to form, particularly during the growth period of the cell
a type of cell wall
primary wall
when formed, expansion in cell size can no longer be expected
secondary wall
- are larger and more centrally located in plant cells
- store enzymes and waste products
water vacuoles
familiarize only:
in mature plant cells, it could occupy 90% of the volume
water vacuoles
familiarize only:
in what form can waste materials inside the vacuoles be in?
in the form of posionous substances that needs to be isolated
e.g. cyanide
carry out photosynthetic function in plants
plastids
example of plastids:
- chloroplasts
- chromoplasts
- leucoplasts
contain chlorophyll which is designed to absorb sunlight in the initial step of photosynthesis
chloroplasts
synthesize and store pigments such as yellow, carotene, xanthophylls, and various red pigments
chromoplasts
- colorless
- store food such as starches, lipids and proteins
- found in storage organs
leucoplasts