Eukaryotic Cell Structure

Question 1

What are eukaryotes?

Answer 1

-an organism consisting of one or more cell that contain DNA in a membrane bound nucleus - separate from the cytoplasm

Question 2

4 examples of eukaryotes

Answer 2

1. Animals
2. Plants
3. Fungi
4. Protists

Question 3

What is the nucleus?

Answer 3

-holds genetic material
-chromatin - consists of DNA and proteins

Question 4

What is the nucleolus?

Answer 4

-makes RNA - made into ribosomes

Question 5

What is the nuclear envelope?

Answer 5

-double membrane that has pore going through the envelope
-allowing large molecules to pass
-has nucleoplasm

Question 6

What is mitochondrian?

Answer 6

-energy generating organelle
-has 2 membranes - inner layer folds = cristae
-matrix formed by cristae - contains enzymes for aerobic respiration = ATP
-DNA + ribosomes in matrix

Question 7

What are ribosomes?

Answer 7

-found in cytoplasm or bound to RER
-site of protein synthesis
-assembly line for nucleus to make proteins from amino acids

Question 8

What is the Golgi apparatus?

Answer 8

-stack of membrane bound flattened sacs
-receives proteins - modifies them by + sugar
-packages them into vesicles
-some are secreted, some are retained

Question 9

What are lysosomes?

Answer 9

-spherical sacs surrounded by a single membrane
-specialised vesicles
-contain powerful digestive enzymes - break down materials

Question 10

What is the rough endoplasmic reticulum?

Answer 10

-series of flattened membrane = cisternae
-studded with ribosomes
-transports protein that were on ribosomes
-some are secreted - some placed on surface of membrane

Question 11

What is the smooth endoplasmic reticulum?

Answer 11

-same structure as RER
-doesn’t have ribosomes
-involved in making + storing lipids

Question 12

What are chloroplasts?

Answer 12

-double membrane bound compartments
-contain chlorophyll - forming grana
-grana are joined by lamellae
-site of photosynthesis - light dependent
-contain DNA + ribosomes - synthesise proteins in chloroplast replication + photosynthesis

Question 13

What is light independent + dependent stages?

Answer 13

-ID = stroma
-D = thylakoids

Question 14

What are permanent vacuoles?

Answer 14

-sac in plant cells surrounded by tonoplast
-keeps the cell firm
-when full = turgid

Question 15

What is the cell wall?

Answer 15

-freely permeable to most substances
-formed outside of membrane
-structural support
-provided by cellulose in plants
-threads of cytoplasm + pores connect cytoplasm of neighbouring plant cells

Question 16

What is cilia?

Answer 16

-hair like projections made from microtubules
-allow movement of substances over surface - in single celled
-move materials last immobile cell - in multicellular

Question 17

What is flagella?

Answer 17

-longer microtubules
-contract for movement
-allow movement for substances over surface in single celled

Question 18

What are centrioles?

Answer 18

-hollow fibres made of microtubules
-2 centrioles at right angles form a centrosome
-organises spindle fibres during division

Question 19

What is the plasma membrane?

Answer 19

-separates interior from exterior
-fluid of lipids, proteins and carbs
-impermeable to ions + water soluble molecules
-provide cell with nutrients
-control internal ion concentrations