3.2 Cells Flashcards
What is the cell surface membrane?
*double layer of phospholipids + larger proteins within bilayer
•controls movement in and out of cell
What is the structure of the nucleus?
•nuclear envelope= in + out
•nuclear pores= pass MRNA out
•chromosomes
•nucleolus
What is the function of the nucleolus?
Site of rRNA production, making ribosomes
What is the function of the nucleus?
•DNA replication
•transcription (mRna)
•genetic code for each cell
What is the structure of mitochondria?
•double membrane:
Inner is cristae which +SA for enzymes
•fluid centre is matrix
•loop of mitochondrial DNA: codes for enzymes for respiration
What is the function of mitochondria?
aerobic respiration to release ATP energy
What is chloroplast?
(Site of photosynthesis)
•double membrane
•thylakoids (stacks of flattened discs) with chlorophyll for light dependent reaction
•fluid stroma-enzymes for light independent reaction
What is the structure of the Golgi body?
•folded membrane stacked= cisternae
•vesicles pinch off from cisternae
What is a golgi vesicle?
Lipids + proteins are packed in special membrane bound parcels and transported
What is the function of the Golgi body?
•+ carb to protein= glycoprotein
•form lysosomes
•modify + pack proteins and lipids in vesicles
What are lysosomes?
*bags of digestive enzymes (hydrolytic enzymes)
•hydrolyses pathogens in phagocytosis
•breaks down dead cells (autolysis)
•exocytosis: release enzymes to outside to destroy material
•digest worn out organelles to reuse materials
What are ribosomes?
*subunits= rRNA + protein
80S = eukaryotic
70S = pro
Not membrane bound
•site of protein synthesis
What is the structure of endoplasmic reticulum?
•rough+smooth ER have folded membranes (cisternae)
•rough has ribosomes on cisternae
What does the rough endoplasmic reticulum do?
Modifies and transports proteins and glycoproteins
What does the smooth endoplasmic reticulum do?
Synthesis + storage of lipids, carbs, cholesterol and steroid hormones
What is the cell wall for plants and fungi?
(Provides structural strength)
Plants: micro fibrils of cellulose polymer
Fungi: chitin (N-containing polysaccharide)
What is the structure of the permanent vacuole?
•filled with fluid surrounded by single membrane (tonoplast)
•solution of mineral salts, sugars and amino acids, waste and pigments
What is the function of the vacuole?
•turgid: support
•temporary store of amino acids and sugars (food)
•pigment colours petals to attract pollination
•absorbs and hydrolyses potentially harmful substances
Why are prokaryotic cells different to eukaryotic cells?
•cytoplasm lacks membrane bound organelles
•smaller ribosomes (70S)
•single circular DNA free in cytoplasm
•DNA not associated with proteins
•cell wall that contains murein (glycoprotein)
+:
•plasmids
•capsule surrounds cell
•flagella
What is a virus and it’s structure?
(Acellular (no cells) and non-living)
•genetic material: RNA or DNA
•protein capsid
•attachment proteins identify + attach to host cells
•some have lipid envelope
How do viruses invade + hijack host cells?
1)attachment proteins bind to host cells receptor
2) DNA or RNA injected into host cell
3)host cell divides as normal + virus is replicated
What is magnification?
How much larger the image size is compared to actual size
What is resolution?
The smallest distance between 2 entities that can still be seen as separate entities
How do you use an optical (light) microscope? + Advantages
Beam of light is condensed using lens to form an image.
•alive + dead cells viewed
•easy sample preparation (no damage)
•cheaper and portable