2.1.1 Features of Eukaryotic Cells

Question 1

features of the nucleus

Answer 1

• stores DNA which is tightly packaged through association with histones, forming chromosomes
• nuclear envelope is composed of double membrane which has nuclear pores which allow mRNA and ribosomes to pass through
• contains cytoplasm called nucleoplasm
• has a nuclear envelope to protect DNA
• site of transcription

Question 2

features of the ribosome

Answer 2

• the site of protein synthesis
• can be found floating freely in the cytoplasm or associated with the RER

Question 3

features of the mitochondria

Answer 3

• produce ATP through Kreb’s cycle and oxidative phosphorylation
• regulates cellular metabolism
• outer membrane controls what comes in and out
• cristae increases surface area
• gel-like matrix contains enzymes for respiration

Question 4

features of cell surface membrane

Answer 4

• it acts as a selective barrier to control the movement of substances in and out the cell
• composed of phospholipid bilayer with embedded proteins for flexibility
• structural support

Question 5

features of lysosomes

Answer 5

• hydrolysis of material ingested by phagocytic cells
• digestion of old or damaged organelles to recycle them
• complete breakdown of dead cells
• exocytosis - release of digestive enzymes

Question 6

features of the rough endoplasmic reticulum

Answer 6

• studded with ribosomes for protein synthesis
• RER cisternae folds and modifies proteins initially then transports the vesicles to the Golgi apparatus

Question 7

features of the smooth endoplasmic reticulum

Answer 7

• synthesise lipids to create things like phospholipids
• synthesise carbohydrates to create things like gluconeogenesis
• detoxifies drugs and harmful metabolic products

Question 8

features of the Golgi apparatus

Answer 8

• modifies proteins and joins them to other things producing lipoproteins, glycoproteins, full proteins
• packages new molecules into vesicles for transport
• forms lysosomes which are vesicles of digestive enzymes

Question 9

features of the chloroplast

Answer 9

• thylakoids (single disc) contain the pigment chlorophyll and the location of the first stage of photosynthesis
• the grana are the stacks of thylakoids which are linked by intergranal lamellae
• the stroma is a fluid-filled chamber which is where the second stage of photosynthesis takes place
• the stroma contains enzymes, starch grains, DNA and ribosomes

Question 10

features of the cell vacuole

Answer 10

• maintain the structure of a cell
• contain sugars and amino acids which may act as a temporary energy store
• contains pigments that colour petals
• regulates internal pH and ion concentration
• helps isolate harmful byproducts from the rest of the cell

Question 11

features of the cell wall

Answer 11

• provide mechanical strength to stop it from bursting
• support the whole plant
• protects against stress and pathogens
• allow for a passage of water across multiple cell walls
• attach cells together with the middle lamella