cell organelles

Question 1

describe the structure of nucleus

Answer 1

nucleus - contains chromatin within the nucleoplasm , which condenses to form chromosomes
it contains a nuclear envelope - double membrane containing pores which allows mRNA to leave and nucleotides to enter
nucleolus- makes RRNA and ribosomes

Question 2

mitochondria

Answer 2

double membrane - folded membrane makes cristae which has a large surface area for ATP synthesis
intermembrane space - high conc of hydrogen ions
matrix -contains circular dna and 70s ribosomes used to make protiens and self replication

Question 3

chloroplast

Answer 3

site of photosynthesis
double membrane
inner membranes are folded into thylakoids and are stacked into grana
stroma - contains circular DNA and 70s ribosomes used to make proteins and self replication.
contains starch grains

Question 4

ribosomes

Answer 4

are made up of protein and RRNA
they are 70 s in organelles and prokaryotic
they are 80s in eukaryotic cells

Question 5

endoplasmic reticulum

Answer 5

they are flattened membrane sacks called cisternae
rough endoplasmic reticulum - covered in ribosomes and proteins are synthesised here
smooth endoplasmic reticulum - no ribosomes and lipids are synthesised here

Question 6

golgi apparatus

Answer 6

stack of flattened cisternae
here the proteins are modified and bud off to be transported

Question 7

lysosomes

Answer 7

-sacks containing lysozymes which are digestive enzymes
they break down unwanted or old organelles taken in by phagocytosis
The fuse to the membrane of vesicles and release lysozymes

Question 8

vacuole

Answer 8

plant cells contain it
it is surrounded by a membrane called tonoplast
these act as storage sites and contain pigments which attract pollinators

Question 9

cell wall

Answer 9

plant - made of cellulose
fungal- made of chitin
prokaryotic - made of murein
stops cell from bursting
it is permeable
between cell walls there are normally plasmodesma which provides cytoplasmic continuity allowing rapid transport of material

Question 10

what is an epithelial cell

Answer 10

It’s in the lining of small intestines and are specialised to maximise absorption of small molecules into the blood
They have microvili to increase surface area
Lots of mitochondria for aerobic respiration to make more atp for uptake of molecules