Cells Flashcards
Whats is the specimen?
Mat. put under the micr
What is the image?
The image is the appearance of this material when viewed under the mic
Resolution
Ability to distinguish two adjacent (but separate) points distinctly
What are the two types of e. mic.?
TEM and SEM
What are the adv of TEM?
1: High magnification
2:High resolution
3: Wavelength of electrons shorter
What are the disadv of TEM?
Nucleus and RER
(in relation to forming, excreting and incorporating proteins into cell membrane)
the nucleolus provides rRNA
Chr within the nucleus contain the genetic code/ DNA has a nucleotide seq
That determines the seq of aa in a pp chain
mRNA carries a copy of this code out of the nucleus/ through the nuclear pores onto the RER
Ribosomes (on RER) are the site of protein/ polypeptide synthesis
Golgi Body
(in relation to how proteins are formed, excreted and incorporated into cell membr)
ER vesicles containing the newly synth (primary) protein bud off RER
and carry it to the forming face of the GA
within the Golgi the primary protein is modified into the final enzyme
Carb/ lipid may be added to make glycoprotein/ lipoprotein
Polypeptides brought together to form quaternary structure
Prosthetic Group may be added
Vesicles and Lysosomes
(in relation to how proteins are formed, excreted and incorporated into cell membr)
Vesicles then bud off the mature face of Golgi
Secretory vesicles will carry enzymes to the cell surf membrane
Where they fuse with it/ release their enzymes
Other vesicles may carry glyco/lipoproteins to surf membr
Where they can become incorporated into the membr as receptors/ recog sites
Lysosomes are also budded off Golgi
They fuse with worn-out organelles that have been enclosed in a membrane/ phagocytosed material
The hydrolytic enz (in the lysosome) then digest the old organelle/ phagocytosed material
Nucleus
i.e
ER
rRNA
mRNA
euch/hetr
Bordered by a double membrane
Pores to allow the movement of large mol between nucleoplasm and cytoplasm
Outer membr of envelope is invaginated to form the ER
The nucleus stores the cell’s genetic material/ chromatin
It also contains the nucleolus which is the site of the synthesis of rRNA (ribosomes)
Euchromatin is the site of transcription of mRNA
Site of DNA replication
Euchromatin is active (since it is unwound) while heterochromatin is inactive (so more dense)
Chloroplast
Thylakoids
Grana
Chl
Stroma
Surrounded by a double membrane
Contains an internal system of membr (lamellae) organised into thylakoids which are stacked to form grana
The lamellae (thylakoids) contain chlorophyll pigments which absorb light
The chloroplast matrix is known as stroma (contains enzymes for light-dependent reactions)
The chloroplast is the organelle of phs
Products of phs are stored as starch grains (and lipid droplets)
Stroma contains small ribosomes/ circular DNA
Mitochondrion
Bordered by a double membrane/ envelope the inner membr of which forms cristae
Increases the sa of membr for enz avail for resp r
The mitochondrion is the organelle of aer resp/ synth of ATP
Matrix contains small rib
Lysosomes
Prod by Golgi bodies
Are vesicles containing powerful lytic enzymes known as lysosomes
Imp in dig of degenerate organelles (membr enclosed and with which the lysosomes coalesce)
On occasion, the lysosomes may release their enzymes thereby digesting the whole cell
Also may fuse with phagosomes containing engulfed/ phagocytosed material
What are the similarities between an animal cell and a bacterial cell?
Both possess a cell membr/ cytoplasm
Cell membr has a fluid mosaic str/ composed of phospholipids and proteins
Both possess ribosomes
Both possess DNA
Both may contain glycogen
What are the differences between an animal and a bacterial cell?
Bacterial cell is much smaller than animal cell
A cell wall surrounds bact cell but not animal cell
Bact cell may also have a capsule/pili
Cell membr of an animal cell contains cholesterol (absent in bact cell membr)
Ribosomes in a bact cell are smaller than those in an animal cell
DNA linear in animal cell while bacterial DNA is circular
DNA associated with histone/ proteins in animal chr while bact DNA lacks proteins
Bact cells may contain plasmids, while animal cells do not
Genetic material is enclosed in a nuclear membr in animal cells/ they possess a nucleus
Bacterial cells contains no membr- bound organelles whilst animal cell does (e.g mit, ER, Golgi body, lysosomes)
Bacterial cells are prokaryotic while animal cells are eukaryotic
Centrioles/ mitotic spindle/ microtubules present in animal cells but not in bact cells
