Structure Flashcards
What is an eukaryotic cell?
It is a membrane bound cell with nucleus and chromosomes present and characterised with other membrane bound organelles
What is a prokaryotic cell?
It is a cell which belongs to the prokaryotes kingdom,know for the lack of nucleus and membrane bound chromosomes
What is a nucleus?
Largest nuclear organelle which is a double membrane surrounded by nuclear envelope which is pores which allows substances e.g RNA to move between nucleus and cytoplasm
Contains chromosomes made protein bound linear DNA
Having the genetic material of the cell
What is a nucleolus?
Largest structure in nucleus be at know for being the site of the synthesis of ribosome
What is the mitochondrion?
Is a double membrane and has an inner membrane which is folded to form cristae and inside of it there is a matrix containing its own enzymes to create respiration
Function:site of aerobic respiration which means glucose and other molecules are broke down to produce ATP through multiple chemical reactions.
What is RER?
a series of flattened sacs called
cisternae containing different range of enzymes.Covered in ribosomes enclosed by a membrane,RER folds and processes proteins made on the ribosomes.
What Is SER?
A system of membrane bounds sacs process and produces lipids and carbohydrates
Synthesis of steroids(lipids hormone)
What is the difference between SER and RER?
RER has ribosomes and makes protein which SER does not
What is Golgi apparatus?
Series of fluid filled flattened and curved sacs with vesicles surrounding the edge
Function:processes and packages protein and lipids and also lysosomes
What is a ribosome?
Intercellular structure composed of 2 sub units (RNA and protein)and are the site of protein production.
No membrane
What are lysosomes?
Are vesicle containing powerful digestive enzymes such as protease these digest large molecules into soluble molecules,bound to a single membrane
Breaks down unwanted cells.
Enabling the cell to recycle components and manage cellular waste
What is a cell wall?
Rigid outer covering made out of cellulose or peptidoglycan
Give cell structure
Cell/plasma membrane what is that?
Lipid bilayer contains protein in/on cell
Regulates movement of substances in cell
(1)Describe the pathway to how an enzyme is secreted
Inside nucleus there is DNA which contains genetic code for enzyme and corresponding is activer when cell needs enzyme
(2)Describe the pathway to how an enzyme is secreted
Transcription:gene is activated and transcended in a mRNA molecule which carries genetic instructions for building the enzyme
(3)Describe the pathway to how an enzyme is secreted
mRNA PROCESS:molecule goes thru moderations like adding a cap and tail to become a mature mRNA.
(4)Describe the pathway to how an enzyme is secreted
Translation:ribosomes in cell read the mRNA and build the enzyme by linking amino acids together
(5)Describe the pathway to how an enzyme is secreted
Protein folding:in the cytoplasm,the newly formed enzyme starts to fold into its functional shape
(6)/(7)Describe the pathway to how an enzyme is secreted
RER:where enzymes are made, moves to the Golgi apparatus for additional processing and sorting
Golgi:moves here for additional processing and sorting
(8)Describe the pathway of how an enzyme is secreted from a cell
Vesicles formation: golgi packages the enzymes into vesicles
(9)Describe the pathway of how an enzyme is secreted from a cell
Secretion:vesicles move to the cell’s membrane and release enzyme through a process (exocytosis)
(10)Describe the pathway of how an enzyme is secreted from a cell
Enzyme function:outside it can catalize specific reactions in the cells environment
Why are there so many folds?
To increase the S.A of cell
What are the prokaryotes and what are the differences between eukaryotic cell?
Smaller than euk(mitochondrion can’t fit as it is to big)
-Cell wall in prokaryotes contain murein(type of glycoprotein).
-smaller ribosomes(70s compared to 80s in euk)
-Lack of nucleus (plasmids are lose in cytoplasm)
-cytoplasm lacks membrane bound organelle.
Example:bacteria cells and cyanbacteria ,archea
What is a centriole?
are hollow cylinders containing microtubules arranged at right angle to each other, involved in producing spindle fibres for cell division.
What is chloroplast structure?
Stroma(liquid substance)
is a alkaline, aqueous fluid which is protein rich and is present within the inner membrane of the chloroplast.
In light independent reaction
Lamella-play a role in light dependent reaction slowing chemicals to pass between grana
Thylakoids system
is a collection of membranous sacks called thylakoids. The chlorophyll is found in the thylakoids and is the sight for the process of light reactions of photosynthesis to happen.
Granum:stakes of thylakoids
Intermembrane Space – It is usually a thin intermembrane space about 10-20 nanometers between inner and outer membrane
Inner,outer membrane which is permeable to small molecule and ions
Lamella:connected to the thylakoids
Explain the hormone secretion from nucleus to cell membrane.
-In the nucleus there is genes which contains instructions to produce a hormone and it is the actived and transcripted into a Messenger RNA and now it goes thru various moderations like adding a cap and a tail now ready for export from nucleus to cytoplasm through the pores
-In cytoplasm the mRNA binds to ribosome to read it and assembles corresponding protein(hormone)
-it is then transported to the Golgi apparatus going through moderation and processes like adding a sugar molecule to be it processed and package them into Vesicles for transport and move towards cell membrane via endomembrane system
-the vesicles fuse with cell membrane through releasing hormone into bloodstream to interned target cell or tissue.
What is tonoplast?
Central membrane surrounding the vacuole(stores salts,minerals pigment and protein,helps maintain water balance by pushing cytoplasm toward cell wall) acts as a barrier controlling substances entering and exiting the vacuole
What is a protoplast?
-A cell with no cell wall
-Often from backeria or plants
(By removal of cell wall)
-Useful in genetic studies and excitements as it allows easy manipulation to genetic code
What factors affect the fluidity and permeability of cell membrane
Temperature:the phospholipids bilayer become more fluid of exposed to high temperatures
Lipid composition:unsaturated fatty acids tend a kink to prevent it to be more fluid whilst saturated tend to have kink making them to be fluid
Chloresterol:the increase,reduces the cell membrane fluidity.
Molecule and ions
Alcohol or ions(calcium) can disrupt the cell membrane integrity and fluidity.
Ions strength:higher salt concentration it can denature proteins in the cell membrane, altering their structure and function affecting the transport and signaling.
What are other factors a affect the permeability of cell membrane?
Lipids raft
Cell membrane protein
Membrane asymmetry
Which organelle doesn’t contain nuclei acid?
Golgi
What does the nucleus contain?abd difference in rna and dna?
Genetic information of cell
And nucleoplasm which contains nucleotides and enzymes needed for DNA and RNA synthesis (both have genetic information but RNA is a single stranded molecule with shorter chain of nucleotides,DNA is double stranded with longer chain.)
What is chromatin?
it is DNA coiled around protein (histones) and this form chromosomes.
And DNA in chromosomes is linear,so they aren’t joint to form a loop.
Why is the chromosomes not visible in when seen through a microscope?
In mitosis chromosomes become highly condensed(visible) especially in metaphase.
What are starch granule?
Is the end product of photosynthesis carbohydrate glucose can be converted into polysaccharide starch stored as starch granule.
Why is there a loop of DNA in chloroplast?
Contains gene for some of the proteins needs for photosynthesis.
What does cell sap contain
dissolves sugars,mineral salts and amino acid
Some may contain other molecules like in plants can contain poisonous chemicals to deter herbivores
-in flower it contain coloured pigment attracting pollinators
Why does the cell sap have low water potential?
Because of the high amount of dissolved sugars and mineral ions
So water moves in by osmosis in vacuole producing a high hydrostatic pressure ,cytoplasm presses against the cell wall so cell is now turgid
Important for plant that don’t have a woody stem (softer) or don’t a significant secondary growth.
