Module 2:Cell structure Flashcards
What makes a cell eukaryotic
it contains a nucleus and membrane bound organelles
What organelles are present in eukaryotic ultrastructure
nucleus
mitochondria
RER
SER
Golgi apparatus
ribosomes
centrioles
lysosomes
What is the role of the nucleus and what structures are within it?
controls all cell activity by controlling the transcription of DNA
it contains a nucleoplasm which is full of chromatin , a nucleolus which synthesises ribosomes and a nuclear envelope which is a double membrane containing pores to allow movement of mRNA
What is the role of the mitochondria and what structures does it contain
to produce ATP during aerobic respiration
surrounded by a double membrane (inner and outer) , a matrix which is empty space and cristae which are folds created to increase the SA
What is the role of the rough endoplasmic reticulum and what is its structure
to fold and process proteins
its a series of interconnected flattened sacs with ribosomes attached to the surface
What is the role of the smooth endoplasmic reticulum and what is its structure
to synthesise and process lipids
its a tubular structure with spaces and has no ribosomes attached to its surface
What is the role of the golgi apparatus
takes proteins and free ribosomes from the RER , and lipids from the SER to process , modify and package , processed molecules bud off in vesicles which are either used in the cell or exit via exocytosis
What is the role of ribosomes
they are the site of protein synthesis and they translate mRNA into amino acids and proteins
What is the role of the centrioles
they are important for the accurate separation of chromosomes during cell division and they create spindle fibres
What is the role of the lysosomes and what is their structure
they are involved in the breakdown of invading cells and foreign material
they are spherical sacs that contain the digestive enzyme lysozime
Plant cells contain the same organelles as animal cells , but what organelles don’t they contain?
centrioles and lysosomes
What extra organelles do plant cells contain
chloroplasts
a permanent vacuole
cell wall
What is the role of chloroplasts and what is their structure
they use carbon dioxide , oxygen and light energy to build sugars
they are surrounded by a double membrane and the inner one is continuous to increase SA
they contain stacks of thylakoid membranes called grana
What are thylakoid membranes the site of …
photosynthesis
What is the role of the vacuole and what is the name of its membrane?
What substance does this membrane contain?
its important in keeping the cell firm
it has a membrane called the tonoplast which is filled with cell sap
What does cell sap contain
sugars enzymes and pigments within a watery solution
What is the role and structure of the cell wall
it provides structure and support to the cell
it is made of cellulose which can act as a carb store
the wall contains pores that can connect 2 cells by their cytoplasm
What is cellulose
a polysaccharide
What are the pores within the cell wall called and what do they allow
plasmodesmata
they allow the exchange and transport of substances between cells
What are prokaryotes
unicellular organisms that have no nucleus and no membrane bound organelles
What structures are always present within prokaryotes
a plasma membrane
DNA is contained in the nucleoid
cytoplasm
ribosomes
peptidoglycan cell wall
Are ribosomes in prokaryotes bigger or smaller than that of eukaryotes
smaller
How do prokaryotic cells reproduce
via binary fission
What other structures can be present in prokaryotes
pili
plasmids
capsule
flagella
What is the role of pili
they are hair-like structures which
attach to other bacterial cells
What are plasmids
a circular piece of DNA
What is the role of the capsule
it is a protective slimy layer which helps the cell to retain moisture and adhere to surfaces
What is the role of flagella
they are tail like structures that are important for locomotion
Describe protein transport in cells
-include the first 2 points
-proteins are produced on the ribosomes
-proteins produced on the surface of the RER are folded and processed in the RER
Describe protein transport in cells
-include the final 3 points
-proteins are transported from the RER to the Golgi apparatus in vesicles
-they are modified in the golgi apparatus
-the golgi packages proteins into vesicles so they can be transported to where they are needed in the cell
What is the role of microtubules?
they are involved in moving chromosomes from the equator to either poles of the cell during mitosis
