Cell function Flashcards
Functions of cell wall
- protect, support and shape of cell
- Fully permeable (large spaces between microfibrils)
functions of cytosol
- provide a liquid env
- Fills space between organelles
phospholipids
differentially permeable to substances
Cholesterol
Fluidity of cell membrane
integral and peripheral proteins
- Transport
- Act as enzymes
- Act as receptors
- Attachment for cells
- Inside cell membrane surface for attachment to cytoskeleton, which provides cell shape and cell motility
Carbohydrates (glycocalyx)
- mediate interactions btwn cells
- Act as identifying markers
- Blood type-absence or presence of antigenic substances on RBC surfaces
Plasmalemma
- Act as boundary btw cell and environment
- Maintain integrity- diff permeable
- Transport processes
- Respond to externa signals
-Hormone receptor
-Recognize cells as innate or foreign - Coms and attachment with other cells
- Excrete extra cellular mats
-Cellular coms through the glycoproteins and glycolipids
Nucleus
- Contains DNA instructions
- Protein synthesis
- Control center that controls all activities
Nuclear pore
Keeps DNA in and let mRNA out
Chromosomes/Chromatin
Dna rep
transcription
Nucleoli
Production of ribosomal RNA(rRNA)
and called the ribosome factory.
Ribosomal proteins are formed in the cytosol and move into nucleolus and bind with rRNA to form ribosomal sub units. They leave the nucleus and combine to form ribosomes
ribosome
Protein synthesis - AA chain (polypeptide chain) to form protein
1, Polysomes and free ribosomes make protein
2. GER make protein
endndoplasmic reticulum
Transport particles
GER
- Protein synthesis
- Contains proteins in cisternae
- Transport particles like proteins through the cell
SER
- Biosynthesis of steroid hormones
- Regulate muscle contractions/concentration of Ca+
3.In the liver
- store and breakdown glycogen
-syn of phospholipids
-detoxification of poisons
Golgi complex
Receives membrane bound secretory vesicles from GER
1. Change new proteins and glycoproteins
2. Packaging of proteins and enzymes (lysosomes) or cell membrane components
3. distribution of secretions in vesicles
-store finished products in cytoplasm or export outside plasmalemma
peroxisomes
- Synthesis and degradation of hydrogen peroxide
2.Degrade fatty acids
3.Metabolise toxins( in liver detoxify alcohol) - Bile acid synthesis
Lysosomes
1.Food: macromolecules enter the cell via endocytosis enclosed in a vesicle. Lyso fuses w v and forms secondary lyso. Macromolecule digested to monomers and released into cytosol for utilization
2. Foreign subs: WBC engulf bacteria via vesicles through fusion and it’s digested by lysosomes
3. Old and worn-out cells -Autolysis- or old and worn-out cell components- autophagy: enclosed and digested by lysosomes
Actin microfilament
2 actin chains in double helix and each chain contains globular proteins
1. Actin and myosin- helps for muscle contractions
2. Polymerize or depolymerize forming structural framework for a cell- eg 1) thin sheath- structural support, endocytosis, exocytosis, cell migratory activity eg2) form microvilli of epithelial cells of alimentary canal- can contract and lengthen the microvilli
3. ) Plays a role in shifting cytoplasmic components and cell movement– Amoeba- and cytoplasmic streaming and amoeboid movements
Cytoskeleton
Supporting framework for organelles
maintains shape of cell
for cellular movement
anchors plasmalemma
supplies a surface for intracellular transport
Mitochondria
aerobic respiration
3 protein filaments of cytoskeleton
- Microfilament
2.Intermediate filament
3.Microtubles
Intermediate filaments
-Structural and strong alpha-keratin fiber network-3 strings of globular proteins
1) Form cytokeratin filaments(epithelial cells)
2) form neuro filaments (neurons)
3) Form Desmin filaments (heart muscle cells)
Microtubules
Polymerize from globular protein subunits and can depolymerize easily. Like a tube
1) Forms spindles in mitosis and cell division
2) anchorage and reinforce organelles
3. Forms centrioles, basal bodies, cilia and flagella
Centrioles and basal bodies
Types of microtubules
1) Give rise to basal bodies which forms cilia and flagella
2) Dtm plane along which cytoplasm will divide during cell division
BASAL BODY
Position Centrosome
Structure 9+0 arrangement
Originate from centrioles
Function Give rise to cilia and flagella
Centrosome
Structure Short, microtubule
Pair perpendicular to each other
9+0 arrangement
Function
Give rise to basal bodies
Cell division
cytology
study of cell function and structure
How do big cells compensate for size
- cytoplasmic streaming
plant cells- organelles and fluids flow together and helps move molecules - Microvilli - inc SA for inc absorption
- More than one nucleus to incr protein syn
- Long, narrow, cylinder - nerve cells- cytoplasm near surface- quick diffusion
cilia and flagella
cilia- casue mvement of liquid past stationary cells by moving back and forth to propel in one direction
flagella- Propel motile cells which use flagellum as an oar for propulsion in fluid like sperm cell
use 9+2 arrangement - 9 groups of 2 microtubules and 1 pair in the center
resolving power
means resolution ability
the ability to distinguish 2 point close to each other as sep pts
Highway of the cell
endoplasmic reticulum
cell
smallest structural and functional unit containing all molecules and structures NB for life
cell doctrine
- Life occurs from cells
- Cells are self producing- cells come from cells
- Structure relates to function
Function of cells
- Reproduction and growth
- Respiration -oxidation
- Contractibility
- Absorption
- metabolism
- irritability/responsiveness
- conductibility
- Secretion and excretion
Explain maximum & minimum size of cells in detail.
Max:
* Natural laws limit upper cells size
* Ineffective for biological communication
* Slower diffusion
* Ratio of nucleus to cytoplasm
Min:
* Any smaller won’t have space for necessary organelles to support life
* Mycoplasm has +-200 organelles
Repeatedly folded plates of memranes with spaces- tubles-vesicles-cisternae- enclosed
Endoplasmic reticulum
control center
nucleus
plant version of peroxisomes
glyoxysomes
function of cristae
incre SA for ele transfer
What is in matrix
ribosomes, enzymes, plasmid, cations
how does the SER form
when GER loses ribosomes and starts synthesizing non protein products
endomembrane system
flow of membranes between the different organelles (e.g. the nucleus or ER) and the
plasmalemma, forming an endomembrane system involved in the synthesis of cell products,
their modification in storage and eventually their final product (e.g. secretion).
whats not included in the endomembrane system
mitochondria
chloroplast
peroxisomes
cytoskeleton
an extended network of supporting filaments
