Eukaryotic Cell Structure

Question 1

What are the 2 types of cells?

Answer 1

Prokaryotic and Eukaryotic

Question 2

What are the characteristics of prokaryotic cells?

Answer 2

• No membrane bound nucleus or *organelles
• Single celled
• Simpler internal structure - single undivided area called cytoplasm

Question 3

*How much of a prokaryote is inside the prokaryotic cytoplasm?

Answer 3

Everything inside the plasma membrane

Question 4

Describe the prokaryotic cytoplasm.

Answer 4

Internal fluid made up of cytosol and cytoskeleton

Question 5

Where do all of the metabolic reactions in a prokaryote occur?

Answer 5

In the prokaryotic cytosol

Question 6

What is the cytosol composed of?

Answer 6

Water, ions and organic molecules

Question 7

What is the cytoskeleton?

Answer 7

A network of fibres inside the cytoplasm

Question 8

What organisms are classed as eukaryotes?

Answer 8

Animals, plants, fungi, single-celled protoctista

Question 9

Define what a eukaryotic cell is.

Answer 9

A cell with a membrane bound nucleus and organelles

Question 10

*How much of a eukaryote is inside the eukaryotic cytoplasm?

Answer 10

Everything between the plasma membrane and nuclear envelope

Question 11

Define organelle.

What do organelles provide?

Answer 11

Membrane-bound compartments with varying functions inside eukaryotic cells

Organelles provide distinct conditions for different reactions

Question 12

Define metabolism

Answer 12

Sum of all chemical reactions that occur within each cell of an organism that provide energy for vital processes and synthesis of new organic material

Question 13

What 2 processes does metabolism involve? Define each of them.

Answer 13

1. Anabolism - Reactions of metabolism that construct molecules from smaller units. These reactions require energy, which comes from the hydrolysis of ATP
2. Catabolism - Reactions of metabolism that break molecules down into smaller units. These reactions release energy.

Question 14

What are the 2 very basic characteristics of a plasma membrane

Answer 14

Selectively permeable
Controls movement of substances into and out of the cell and organelles
Fragile

Question 15

What does the nucleus contain?

Answer 15

Coded genetic information in the form of DNA

Question 16

What is the function of DNA

Answer 16

Direct protein synthesis

Question 17

What surrounds the nucleus?

What is the function of this structure?

Answer 17

1. Double membrane nuclear envelope

2. Protect the nucleus from damage in the cytoplasm

Question 18

What does the nuclear envelope contain?

What is the function of this structure?

Answer 18

1. Nuclear pores

2. Allow molecules to move in and out of the nucleus

Question 19

Why can’t DNA leave the nucleus? How does DNA solve this issue?

Answer 19

DNA itself is too large to fit through the nuclear pores.

To get over this issue, DNA is transcribed into smaller RNA molecules, which can then leave through the pores

Question 20

How are chromosomes formed?

Answer 20

1. DNA associates with histones (proteins that form a complex with DNA called chromatin) to form chromatin (Uncondensed DNA in a complex with histones)
2. Chromatin coils and condenses to form chromosomes (Structures of condensed and coiled DNA in the form of chromatin)

Question 21

Where is the nucleolus?

Answer 21

Inside the nucleus

Question 22

What is the function of the nucleolus?

Answer 22

Produce ribosomes

Question 23

What is the nucleolus composed of?

Answer 23

Proteins and RNA

Question 24

What is the function of RNA in the nucleolus?

Answer 24

RNA is used to produce ribosomal RNA (rRNA), which is then combined with proteins to form ribosomes

Question 25

Describe the structure of the mitochondria.

Answer 25

* Double membrane | * Inner membrane = highly folded to form cristae

Question 26

Define cristae

Answer 26

Fold of inner mitochondrial membrane. | Increases SA for electron transfer chain to occur.

Question 27

What is the function of cristae membranes in terms of what they contain?

Answer 27

Contain enzymes used in aerobic respiration

Question 28

Can mitochondria produce their own enzymes?

Answer 28

Yes

Question 29

Can mitochondria reproduce themselves?

Answer 29

Yes

Question 30

Do mitochondria contain DNA? Where is it located?

Answer 30

Yes - mtDNA - present in the matrix

Question 31

What are vesicles?

Answer 31

Membranous sacs with storage and transport roles

Question 32

Describe the structure of vesicles

Answer 32

Single membrane with fluid inside

Question 33

What are lysosomes? What do they contain?

Answer 33

Specialised vesicles that contain hydrolytic enzymes

Question 34

What is the function of lysosomes?

Answer 34

* Break down waste material in cells * Break down pathogens ingested by phagocytes * Apoptosis - programmed cell death

Question 35

What is the cytoskeleton

Answer 35

A network of fibres present throughout the cytoplasm

Question 36

What are the 4 functions of the cytoskeleton?

Answer 36

* Maintains the shape and stability of cells * Holds organelles in place * Controls cell movement * Controls movement of cells within organelles

Question 37

What are the 3 components of the cytoskeleton?

Answer 37

1. Microfilaments 2. Microtubules 3. Intermediate fibres

Question 38

Describe the structure of microfilaments.

Answer 38

Contractile fibres formed from actin

Question 39

What is the function of microfilaments?

Answer 39

* Cell movement | * Cell contraction during cytokinesis (where a eukaryotic cytoplasm divides into 2 daughter cells)

Question 40

What is the function of microtubules?

Answer 40

* Determine cell shape | * Act as tracks for movement of organelles e.g. vesicles

Question 41

What do microtubules form?

Answer 41

Spindle fibres

Question 42

What is the function of intermediate fibres?

Answer 42

* Maintain mechanical strength of cell | * Maintain cell integrity

Question 43

What are centrioles?

Answer 43

Components of the cytoskeleton of eukaryotes, (apart from flowering plants and most fungi) composed of microtubules

Question 44

What do 2 centrioles form?

Answer 44

Centrosome

Question 45

Where are flagella and cilia found?

Answer 45

Extending from some cell types

Question 46

What is the function of flagella?

Answer 46

* Cell motility | * Sensory organelles

Question 47

What are the 2 types of cilia?

Answer 47

Mobile and stationary

Question 48

What part of the body do sensory cilia have a role in?

Answer 48

Sensory organs e.g. nose

Question 49

What is the function of mobile cilia?

Answer 49

Beat in a rhythmic manner, creating a current which causes adjacent fluid and objects to move

Question 50

Give 2 anatomical examples and functions of cilia.

Answer 50

Present in trachea - move mucus away from lungs | Present in fallopian tubes - move egg cells from ovary to uterus

Question 51

Describe the structure of 1 cilium.

Answer 51

2 central microtubules surrounded by 9 pairs of microtubules arranged in a wheel, known as the 9+2 arrangement

Question 52

What is the endoplasmic reticulum?

Answer 52

A network of membranes enclosing flattened sacs called cisternae

Question 53

What is the endoplasmic reticulum connected to?

Answer 53

Outer membrane of the nucleus

Question 54

What does the smooth endoplasmic reticulum have a role in?

Answer 54

Synthesis and storage of lipids and carbohydrates

Question 55

What's the structural difference between the SER and RER?

Answer 55

RER has ribosomes bound to the surface

Question 56

What does the rough endoplasmic reticulum have a role in?

Answer 56

Synthesis and transport of proteins

Question 57

Where are ribosomes located?

Answer 57

Free floating in cytoplasm or attached to RER. | Also found in mitochondria, chloroplasts and prokaryotes.

Question 58

Do ribosomes have a membrane?

Answer 58

No

Question 59

What are ribosomes made up of? Where does this originally come from?

Answer 59

RNA - made in nucleolus

Question 60

Describe the structure of the Golgi apparatus.

Answer 60

Formed from an interconnected network of cisternae/flattened membranous sacs

Question 61

What is the function of the Golgi apparatus?

Answer 61

Modification and packaging of proteins

Question 62

State the process of protein synthesis. | *Spec says it's not needed

Answer 62

1. Proteins are synthesised on ribosomes bound to EP | 2.