2.1.1. Structure of Eukaryotic cells

Question 1

What is the structure of the nucleus in eukaryotic cells?

Answer 1

Nuclear envelope (double membrane), nuclear pores, nucleoplasm (jelly-like material), chromosomes = protein-bound linear DNA, nucleolus

Question 2

What is the nucleolus?

Answer 2

Smaller sphere where rRNA and ribosomes are produced

Question 3

What is the function of the nucleus in eukaryotic cells?

Answer 3

Site of DNA replication and transcription; contains the genetic information for each cell

Question 4

What is the structure of the smooth endoplasmic reticulum in eukaryotic cells?

Answer 4

Folded membranes (cisternae)

Question 5

What is the structure of the rough endoplasmic reticulum in eukaryotic cells?

Answer 5

Folded membranes (cisternae), ribosomes on surface

Question 6

What is the function of the smooth endoplasmic reticulum in eukaryotic cells?

Answer 6

Synthesis of lipids; stores lipids and carbohydrates

Question 7

What is the function of the rough endoplasmic reticulum in eukaryotic cells?

Answer 7

Protein synthesis (ribosomes)

Question 8

What is the structure of the golgi apparatus in eukaryotic cells?

Answer 8

Folded membranes (cisternae); secretary (golgi) vesicles pinch off from the cisternae

Question 9

What is the function of the golgi apparatus in eukaryotic cells?

Answer 9

Transport, modify and store lipids; form lysosomes

Question 10

What is the structure of lysosomes in eukaryotic cells?

Answer 10

Vesicles of digestive enzymes (e.g. phagocytosis)

Question 11

What is the function of lysosomes in eukaryotic cells?

Answer 11

Hydrolyse phagocytic cells; completely break down dead cells; exocytosis -> release enzymes to outside of the cell to destroy material; digest worn-out organelles for reuse of materials

Question 12

What is the structure of mitochondria in eukaryotic cells?

Answer 12

Double membrane; inner membrane (cristae); fluid centre (mitochondrial matrix); loop of mitochondrial DNA

Question 13

What is the function of mitochondria in eukaryotic cells?

Answer 13

Site of aerobic respiration; site of ATP production; DNA codes for enzymes needed in respiration

Question 14

What is the structure of ribosomes in eukaryotic cells?

Answer 14

Small, made up of two subunits: protein and mRNA; 80s = large ribosome in eukaryotic cells

Question 15

What is the function of ribosomes in eukaryotic cells?

Answer 15

The site of protein synthesis

Question 16

What is the structure of the vacuole in eukaryotic cells?

Answer 16

Filled with fluid; surrounded by a single membrane (tonoplast)

Question 17

What is the function of the vacuole in eukaryotic cells?

Answer 17

Makes cells turgid, providing support; temporary store of sugars + amino acids; pigments may colour petals, thus attracting pollinators

Question 18

What is the structure of chloroplasts in eukaryotic cells?

Answer 18

Surrounded by a double membrane; contains thylakoids (folded membranes embedded with pigment); fluid filled stroma (contains enzymes for photosynthesis)

Question 19

What is the function of chloroplasts in eukaryotic cells?

Answer 19

Site of photosynthesis

Question 20

What is the structure of the cell wall in eukaryotic cells?

Answer 20

Plants: made of microfibrils of the polymer, cellulose; Fungi: made of chitin

Question 21

What is the function of the cell wall in eukaryotic cells?

Answer 21

Provide structural strength to the cell

Question 22

What is the structure of the plasma membrane in eukaryotic cells?

Answer 22

Found in all cells; phospholipid bilayer - molecules embedded in and attached on the outside (e.g. proteins, carbs)

Question 23

What is the function of the plasma membrane in eukaryotic cells?

Answer 23

Controls the entrance and exit of molecules

Question 24

Describe the difference in structure between the RER and SER.

Answer 24

In RER, ribosomes are present.
In SER, ribosomes are not present and SER is more tubular in appearance

Question 25

What are the cell walls of fungi made up of?

Answer 25

chitin

Question 26

What are the two types of ribosomes and where are they found?

Answer 26

80S ribosomes - found in eukaryotes 70S ribosomes (smaller) - found in prokaryotes (as well as eukaryotic chloroplasts and mitochondria)

Question 27

What is the difference in function between the RER and SER.

Answer 27

RER synthesises proteins and glycoproteins (as it contains ribosomes). SER only synthesises, transports and stores lipids and carbohydrates (no ribosomes for protein synthesis

Question 28

Where are ribosomes found?

Answer 28

cytoplasm RER

Question 29

The diagram shows a mitochondrion. Name parts labelled X and Y.

Answer 29

X - Cristae Y - Matrix

Question 30

The electron micrograph shows part of a chloroplast. Name the main substance present in the part labelled C. (1)

Answer 30

Starch

Question 31

Describe and explain the effect on the organelle of placing it in the hypotonic solution. (4)

Answer 31

(outer) membrane breaks down / inner membranes / grana separate; solution has a higher / less negative water potential; (accept description of relative concentrations) water moves into organelle / chloroplast by osmosis / from higher to lower water potential / into more concentrated solution; (reject into cell) organelle swells / increase in pressure and bursts;

Question 32

Define organ and give an example, including the tissues it is made of.

Answer 32

Group of organised different tissues; joined and working together to perform a particular function

Question 33

Define organ system and give an example.

Answer 33

Group of organised organs; working together to perform a particular function nervous system

Question 34

Define tissue and give 2 examples.

Answer 34

Group of organised specialised cells; joined and working together to perform a particular function; often with the same origin epithelial tissue - lines surfaces of animal organs xylem tissue - gives mechanical support and transports water

Question 35

Define the term Eukaryotic cell

Answer 35

DNA is contained in a nucleus, contains membrane- bound specialised organelles