Cell Structure, Evolution and Protein Sorting

Question 1

What is a cell?

Answer 1

The basic unit of life

Question 2

Name the 4 types of tissues

Answer 2

Muscle
Epithelial
Nervous
Connective

Question 3

What are the 5 Organisation levels?

Answer 3

Cell
Tissues
Organ
Organ System
Organism

Question 4

How do we know something is alive?

Answer 4

Living things are made of cells. Something is alive if the following things take place:
Respiration
Movement
Nutrition
Growth
Reproduction
Sensitivity
Excretion

Question 5

Explain the Schleiden and Schwann Cell Theory

Answer 5

The cell is the fundamental unit of structure and function in living things

All organism are made up of one or more cells

Cells arise from other cells through cellular division

Question 6

Explain the Endosymbiotic Theory for Animals

Answer 6

Plasma membrane starts to folds and endomembrane components start to form including the nucleus and endoplasmic reticulum

Ancestral eukaryote consumed aerobic bacteria that evolved into mitochondria

Question 7

How is the endosymbiotic theory different for plants?

Answer 7

They have an extra stage

Early eukaryotes consumed photosynthesis bacteria that evolved into chloroplast.

Question 8

What are the 3 domains of life?

Answer 8

Bacteria
Archaea
Eukaryote

Question 9

What domain do prokaryotes belong to?

Answer 9

Archaea or bacteria

Question 10

What domain do Eukaryotes belong to?

Answer 10

Eukaryote

Question 11

Explain what Archaea are and give names of environments where you can find them

Answer 11

Extremophiles that live in extreme environments like bigs, salt lakes and volcanoes

Question 12

Explain the different types of bacteria are

Answer 12

E.coli found in intestine

Cyanobacteria - role in ecology and evolution

Question 13

Explain what viruses are

Answer 13

Viruses are smaller than bacteria and contain a simple structure.

Question 14

Explain the structure of viruses

Answer 14

Nucleic acid genome

Protein capsid - protects genetic material

Lipid Envelope - Some e.g influenza

Question 15

Are viruses alive?

Answer 15

They are not alive as they cannot reproduce by themselves and they also cannot carry out metabolic reactions

Question 16

Explain the 3 types of structure of Prokaryotes, give examples

Answer 16

Rods, Balls and Helices

Examples: E.coli, Streptococcus, Enterococcus

Filamentous

Examples: Helicobacter pylori, Cyanobacteria

Question 17

What are Gram-negative bacteria and give examples

Answer 17

Bacteria that’s are resistant to antibiotics.

Examples: E.coli, Pseudomonas

Question 18

What colour and shape under a microscope are gram-negative bacteria?

Answer 18

Pink either ball or rod shape

Question 19

What colour and shape under a microscope are gram-positive bacteria?

Answer 19

Purple either ball or rod shape

Question 20

What are gram-positive bacteria and give examples

Answer 20

Bacteria that contain thick cell walls . When gram testing is carried out the cell wall becomes purple

Examples: Streptococcus, Bacillus

Question 21

Steps to carry out Gram Staining

Answer 21

Apply a crystal violet dye - purple in colour

Add iodine to form complex

Wash with Alcohol

Apply safranin

Gram-positive = Purple

Gram-negative = Pink

Question 22

Explain the difference in structure between prokaryotic and eukaryotic cells

Answer 22

Eukaryotic cells contain a nucleus which cantinas genetic material in the form of chromosomes

Prokaryotic cells contain no nucleus, their genetic material is contained within circular pieces of DNA

Prokaryotic cell contain a cell wall made out of peptidoglycan

Eukaryotic cells contain membrane bound organelles e.g. Mitochondria, Endoplasmic reticulum, ribosomes, Golgi. Plant cells have chloroplasts

Question 23

What is the function of the nucleus?

Answer 23

Site of ribosomal RNA synthesis contain all the genetic information of the body.

Question 24

Role of Endoplasmic Reticulum

Answer 24

Lipid Synthesis

Detoxification (liver)

Calcium Storage (muscle)

Question 25

Role of Rough Endoplasmic Reticulum

Answer 25

Synthesis of proteins which are secreted from the cell and the incorporated into the plasma membrane and transported to a different organelle where protein modification can take place (e.g. making a glycoprotein)

Question 26

Role of the Golgi Apparatus

Answer 26

Further Procession of secreted proteins and sorting proteins into vesicles, lysosomes formation and vesicles are transported

Question 27

Role of Lysosomes

Answer 27

Membrane sacs that contain digestive enzymes - hydrolytic enzymes

Question 28

Role of Vacuoles

Answer 28

Found in plants and animal cells. Used for storage of fluid nutrients and waste products

Question 29

What is the route of how proteins are made?

Answer 29

Nuclear Envelope

Endoplasmic reticulum - rough and smooth

Golgi Apparatus

Transport vesicles

Lysosomes

Vacuoles

Question 30

Role of Peroxisomes

Answer 30

Breakdown amino acids and fatty acids by an oxidation reaction in the liver or kidney

Question 31

Structure and Role of Mitochondria

Answer 31

Double membrane bound organelle found in most eukaryotic cells.

Site of Respiration, uses ATP to generate chemical energy

Contains its own DNA

Question 32

Structure and Role of Cell Membrane

Answer 32

Controls and entry and exit of substances

Phospholipid belayer - hydrophilic head (attracts water) and hydrophobic tail (repels water)

Contains protein channels for transport - carrier proteins, aquaporins

Question 33

Name 5 functions of membranes

Answer 33

Compartmentalise Cell

Protect Cells

Control Movement of Molecules

Communication to surrounding cells

Transmit signals

Question 34

Function of Ribosomes

Answer 34

They read mRNA and bind to tRNA to synthesize polypeptides and proteins

Question 35

How do proteins move between compartments?

Answer 35

Nuclear pores

Across membranes via protein translocators

Within vesicles (e.g. between ER and Golgi)

Question 36

Sorting Proteins Co-translational Import Route

Answer 36

Nucleus, RER, Golgi (vesicles), exported outside of the cell or goes to the lysosome

Question 37

Sorting Proteins Post-translational Import

Answer 37

Nucleus, Ribosome

Nucleus, Ribosome, Mitochondria, Peroxisome

Question 38

Role of Chaperones in protein folding

Answer 38

Help proteins to fold properly during protein synthesis and stop them from unwinding during translocation

Question 39

Explain how single recognition particle works

Answer 39

Synthesis begins on a free ribosome

When the polypeptide chain contians about 20 amino acids the ER signal sequence is recognised by the sinal recognition particle

Partical binds to sinal seqeunce and protein synthesis stops

The complex of the ribosome and signal recognition particle encounter a specific signal recognition particle receptor (docking protein) on the ER

This caused the polypeptide chain to be directed to the protein translocator. The signal recognition particle and is receptor are released

Protein synthesis can continue and polypeptides can then go through the membrane via a channel protein

The single sequence maybe cleaved off by an enzyme called signal peptidase, Some proteins do not undergo this step but instead retain their sig\nl sequence.