Cell Structure

Question 1

Vacuole
- structure
- function

Answer 1

• membrane called tonoplast filled with cell sap (watery solution filled with sugars enzyme and pigment), spherical sac surrounded by a single membrane
• sugar and amino acid act as temporary food store,
  Pigment colour petals attract pollinating insects
  Keeps cell structure

Question 2

Ribosomes
- function

Answer 2

• assembles amino acids to form proteins that are essential to carry out cellular functions
• DNA produces mRNA by process of DNA transcription
• mRNA synthesised in nucleus and transported to cytoplasm for protein synthesis
• proteins synthesised in cytoplasm are used in cytoplasm
• protein synthesised by bound ribosomes are transported out of the cell

Question 3

Ribosomes
Structure
tRNA and mRNA

Answer 3

Has 2 sub units:
- sight of protein synthesis in a cell
- assembly line for coded info from nucleus

t- specified amino acids into order to process protein synthesis
m- served as messenger between genes and proteins

Question 4

The nucleus
- structure

Answer 4

• has holes called nuclear pores going through envelope so molecules can pass through
• nuclear envelope is a dense spherical structure surrounding the nucleus made of two membranes with fluid separating

Question 5

The nucleus
- function
- chromatin

Answer 5

• holds almost all cells genetic material
• makes RNA and ribosomes pass through cytoplasm and proteins assembled in them
• consists of DNA and proteins, has instructions for making protein which regulate cell activity
  When Cell divides condenses into visible chromosomes

Question 6

Mitochondria
- structure

• function

Answer 6

• surrounded by two membranes
• inner layer folds inwards forming Cristae, projects into liquid called matrix
• inner membrane coated in enzymes, catalyse reaction of aerobic respiration to produce ATP
• where adenosine triphosphate is produced

Question 7

Mitochondria
- matrix
- cristae

Answer 7

• contains proteins, lipids, ribosomes and DNA, enzymes used in resp found in matrix
• extension of inner membrane , large SA for enzyme attachment and other proteins in respiration

Question 8

Rough Endoplasmic Reticulum
- structure
- function

Answer 8

• Flattened membrane bounded sacs studded with ribosomes
• transports proteins made on attached ribosomes, some secreted from cell, some on cell surface membrane

Question 9

Smooth Endoplasmic Reticulum
- structure
- funtions

Answer 9

• same structure as rough ER but no ribosomes
• makes lipids needed in the cell

Question 10

Lysosome
- structure
- lysozyme
- formed when

Answer 10

• Small structure with cell holding fluid and enclosed by lipid bilayer, contain enzymes made by ribosomes and enzymes isolated by the rest of the cell before release to outside or phagocistic vesicle of cell
• powerful digestive enzyme
• Golgi apparatus contain enzymes (protease and lipase) inside membrane vesicles

Question 11

Lysosome
- function

Answer 11

• hold enzymes to break down material
  -hydrolyse material like bacteria ingested by phagocyte cell
• release enzymes to outside cells
• Digest worn out organelles to reuse chemicals
• break down cells once died
• impervious membrane helps protect the rest of the cell from digestive enzymes inside lysosome which will digest the rest of the cell

Question 12

Golgi apparatus
- structure

Answer 12

• cisternae- stack of membranes that make up flattened sacs
• small round hollow structures called ventricles
• more compact to SER but similar structure

Question 13

Golgi apparatus
- function

Answer 13

• add carbohydrates and proteins to form glycoproteins
• produce secretory enzymes
• secrete carbohydrates used jn making cell walls in plants
• transport modify and store lipids
  -form lysosomes

Question 14

Golgi apparatus
- proteins and lipids

Answer 14

• produced by ER
• passed through Golgi in strict sequence
• modified by adding non protein components
• labels to be sorted and sent to correct destinations
• modified proteins and lipids transported to Golgi vessciles which move to cell surface and fise w membrane and release contents to outside

Question 15

Cell wall
- structure

Answer 15

• no. polysaccharides such as cellulose
• thin layer (middle lamela) cements cells next to each other
• pores in cell wall called plasmo dermata, connect cells by cytoplasm so can exchange substance

Question 16

Cell wall
- function

Answer 16

• strengthens the cell so it doesn’t burst under pressure from osmosis
• allows water to pass through contributing to movement in the plant
• can function of carbohydrates store by varying amounts of cellulose it holds
• cellulose fibres allow substance to dissolve through wall easily
• allows small molecules through but not large as they harm the cell

Question 17

Chloroplast
- structure

Answer 17

• 2 membranes separated by fluid filled space
• inner membrane continuous w network of thylakoids
• stack is called a granum
• chlorophyll molecules on membranes

Question 18

Chloroplast
- function

Answer 18

• site of pss
• light energy used to derive carbohydrates from co2

Question 19

Difference between prokaryotic and eukaryotic cells

Answer 19

• much smaller
• no membrane bound organelles
• smaller ribosomes
• no nucleus
• cell wall contains murein