W2 Prokaryotes and Eukaryotes

Question 1

Examples of unicellular organisms:

Answer 1

All bacteria, protozoa, unicellular algae, unicellular fungi

Question 2

Give examples of Multicellular organism

Answer 2

Pluricellular fungi, algae, parasites, plants, animals

Question 3

Features of a RBC (5)

Answer 3

Transport oxygen.
Biconcave shape
No nucleus
Contain haemoglobin
Small and flexible

Question 4

What are the functions of Nerve cells? (neurons)
What is their structure?

Answer 4

Transmit electrical impulses to other nerve cells, muscle or gland cells in response to the environment stimuli

Thin and long cells

Question 5

How is the human body organised into levels of increasing complexity?

Answer 5

Cell, tissue, Organ, Organ System

Question 6

Light microscope function

Answer 6

To observe living cells in a tissue and some internal structures

Question 7

Fluorescence microscope function

Answer 7

Fluorescence signals can be detected through excitation of fluorophores.

Function- To visualise and monitor the localisation of labelled molecules within a cell or tissue.

Question 8

What is an Electron microscope? (EM)

Answer 8

Technique for obtaining high resolution images, using a beam of electrons (very short wavelengths) as the source of illuminating radiation.

Question 9

What are the two types of electron microscopes?

Answer 9

TEM- Transmission electron microscope
SEM- Scanning electron microscope

Question 10

What is the practical resolution limit of a modern EM?

Answer 10

Around 2nm

Question 11

What are the 4 major organic macromolecules?

Answer 11

Carbohydrates/Polysaccharides
Proteins
Lipids
Nucleic acids

Question 12

What are macromolecules?

Answer 12

Polymers made by specific
repeating molecular units, monomers

Question 13

What are monomers?

Answer 13

▪ building blocks or subunits
▪ smallest units of molecules that can join with each other to form larger molecules, polymers

Question 14

What is anabolism?

Answer 14

Building up
Cells link monomers together to form a polymer
through polymerisation or condensation reactions

Question 15

What is catabolism?

Answer 15

Breaking down
polymers are broken down into
smaller molecules by hydrolysis

Question 16

What is Anabolism?

Answer 16

Catabolism and Anabolism reactions

Question 17

What are the polymers made from fatty acids and their function?

Answer 17

• Lipids
• Energy storage/ Biomembranes/hormones

Question 18

What are the polymers made from amino acids and their function?

Answer 18

• Proteins/Peptides
• Structure/ Enzymes/ Multiple functions

Question 19

What are the polymers made from sugars and their function?

Answer 19

• Oligo/Polysaccharides
• Energy source

Question 20

What are the polymers made from nucleotides and their function?

Answer 20

• Nucleic acids (DNA/RNA)
• Store/encode genetic information/ energy transfer

Question 21

What are the 2 types of distinct cell?

Answer 21

Prokaryotes and Eukaryotes

Question 22

What are the 3 ways that prokaryotes and eukaryotes differ?

Answer 22

Prokaryotes
- WITHOUT nucleus
- ONLY ONE compartment
- Simple internal organisation

Eukaryotes
- WITH nucleus
- Internal membranes that enclose the organelles - Complex organisation

Question 23

Prokaryotes:
Monocellular or multicellular?
Smaller or bigger than eukaryotes?
What are the 2 cellular domains?

Answer 23

Mostly monocellular
Smaller and simpler than eukaryotic cells
Bacteria and Archaea
- Structurally similar but different biochemical abilities

Question 24

Where do archaea bacteria live?

Answer 24

In normal habitats but most of them grow at extreme environmental conditions (pH, temp, salt conc)

Question 25

Overview of prokaryotic cell structure:

Answer 25

* Membrane-enclosed nucleus is absent * Lack of membranous organelles * Simple internal structure External Glycocalyx/capsule and different appendages *Tough protective coat (cell wall), around the plasma membrane *Single internal compartment containing the cytoplasm and the genome

Question 26

What are the prokaryotic cell surface layers?

Answer 26

Plasma membrane Cell wall Glycocalyx

Question 27

What is the plasma membrane?

Answer 27

A flexible lipid bilayer membrane, made up phospholipids and proteins. Do not contains sterols.

Question 28

What is the cell wall?

Answer 28

A rigid structure composed of peptidoglycan. Different in Gram +/- Maintenance of cell shape and structural integrity

Question 29

What is a Glycocalyx? What does it protect the cell against?

Answer 29

Gelatinous coating composed of polysaccharides or polypeptides If organised (capsule) If loosely organised and attached (slimy layer) ➢ It protects the cell against dehydration, immune system (phagocytosis) and antibiotics. ➢ It also an adherence factor.

Question 30

Intracellular composition of a prokaryote:

Answer 30

- Cytoplasm- a gel-like internal fluid - Singular circular genomic DNA in the nucleioid - Not associated with histone proteins - No nucleus

Question 31

Name some prokaryotic cell appendages:

Answer 31

FLAGELLUM: (pl flagella) which are whip-like structure Locomotion- Act as a sensory structure Fimbriae/pili- Short, fine, hair-like (up to 1,000) - Help the cell to stick/attach to a surface - Twitching motility SEX PILUS- Rigid hair-like tubular structures, larger than fimbriae - Allow the attachment to other cells (females) to transfer plasmids/DNA

Question 32

Overview of eukaryotic cells?

Answer 32

* In unicellular (e.g. protozoa and yeasts) and in multicellular organisms (e.g. animals) * Bigger and more elaborate than Prokaryotes * Except for plant and fungal cells, the cell wall is NOT PRESENT in animal/human cells! * All eukaryotic cells have a nucleus * Many membrane-enclosed organelles

Question 33

What is the cytoplasm?

Answer 33

All of the material inside the cell BUT outside of the nucleus It includes cytosol and the various organelles Highly organised and dynamic

Question 34

What is cytosol?

Answer 34

- The part of the cytoplasm that is not contained within organelles - The dense and viscous gel-like fluid to support and protect organelles