4.1.2

Cell Signalling

Test yourself on Cell Signalling

Test your knowledge with free interactive questions on Seneca — used by over 10 million students.

Signal Recognition

Cell signaling pathways begin when the ligand binds to a receptor, a protein that is embedded in the plasma membrane of the target cell or found in the cell cytoplasm.

Secretion & transport

Secretion & transport

  • Signals can be transmitted over longer distances by using chemical signaling.
  • Chemicals (ligands) are secreted from cells and travel in the blood to their target cells.
  • For example, signals from distant cells are called endocrine signals. They originate from endocrine cells.
    • Endocrine cells are located in endocrine glands, such as the thyroid gland, the hypothalamus, and the pituitary gland.
Reception

Reception

  • Cell signaling pathways begin when a ligand binds to a receptor, a protein that is embedded in the plasma membrane of the target cell or found in the cell cytoplasm.
  • The receptors are very specific, and each ligand is recognized by a different one.
    • This stage of the pathway is called reception.
  • Ligands can be peptides, small chemicals, drugs, and others.
Non-polar compounds

Non-polar compounds

  • Molecules that are nonpolar, such as steroids, diffuse across the cell membrane and bind to internal receptors.
  • In turn, the receptor-ligand complex moves to the nucleus and interacts with cellular DNA.
    • This changes how a gene is expressed.
Polar ligands

Polar ligands

  • Polar ligands, on the other hand, interact with membrane receptor protein.
  • Some membrane receptors work by changing conformation so that certain ions, such as Na+ and K+, can pass through the plasma membrane.
  • Other membrane receptors interact with a G-protein on the cytoplasmic side of the plasma membrane, which causes a series of reactions inside the cell.
    • Receptors coupled to G-proteins are a good example of a receptor-type found in eukaryotic cells.
Multiple receptors

Multiple receptors

  • It is important to keep in mind that each cell has a variety of receptors, allowing it to respond to a variety of stimuli.
  • Some receptors can bind several different ligands; for example, odorant molecules/receptors associated with the sense of smell in animals.
    • Once the signaling molecule and receptor interact, a cascade of events called signal transduction usually amplifies the signal inside the cell.
Jump to other topics
1

Cell Structure

1.1

Cell Structure

1.1.1Studying Cells - Microscopes1.1.2Introduction to Eukaryotic & Prokaryotic Cells1.1.3Ultrastructure of Eukaryotic Cells1.1.4Ultrastructure of Eukaryotic Cells 21.1.5Ultrastructure of Eukaryotic Cells 31.1.6Prokaryotic Cells1.1.7Viruses1.1.8End of Topic Test - Cell Structure1.1.9Exam-Style Question - Microscopes1.1.10A-A* (AO2/3) - Cell Structure
2

Biological Molecules

2.1

Testing for Biological Modules

2.1.1Tests for Sugars & Starch2.1.2Tests for Lipids & Proteins
2.2

Carbohydrates & Lipids

2.2.1Monomers & Polymers2.2.2Carbohydrates2.2.3Examples of Carbohydrates2.2.4Triglycerides & Phospholipids2.2.5Types of Fatty Acids2.2.6Exam-Style Question - Carbohydrates2.2.7End of Topic Test - Carbohydrates & Lipids
2.3

Proteins

2.3.1Amino Acids & Overview of Protein Structure2.3.2Primary & Secondary Structure2.3.3Tertiary & Quaternary Structure2.3.4Globular & Fibrous Proteins2.3.5Haemoglobin2.3.6Collagen2.3.7End of Topic Test - Proteins
2.4

Water

2.4.1Water Structure & Function2.4.2End of Topic Test - Water
3

Enzymes

3.1

Enzymes

3.1.1Enzyme Action3.1.2Factors Affecting Enzyme Activity3.1.3Factors Affecting Enzyme Activity 23.1.4A-A* (AO2/3) - Enzymes
4

Cell Membranes & Transport

4.1

Biological Membranes

4.1.1Fluid Mosaic Model4.1.2Cell Signalling4.1.3End of Topic Test - Biological Membranes4.1.4Exam-Style Question - Membranes
4.2

Movement Into & Out of Cells

4.2.1Passive Movement Across the Membrane4.2.2Active Movement Across the Membrane4.2.3Osmosis4.2.4Osmosis & Plant Cells4.2.5Surface Area to Volume Ratio4.2.6Adaptions to Surface Area to Volume Ratio4.2.7Calculations - Volume4.2.8Calculations - Surface Area
5

The Mitotic Cell Cycle

5.1

Replication & Division of Nuclei

5.1.1Chromosomes5.1.2The Cell Cycle5.1.3Mitosis5.1.4Role of Mitosis5.1.5Stem Cells5.1.6Mitosis & Cancer5.1.7End of Topic Test - Replication & Division5.1.8A-A* (AO2/3) - Cell Cycle & Transport
6

Nucleic Acids & Protein Synthesis

6.1

Nucleic Acids

6.1.1Introduction to DNA & RNA6.1.2Nucleotides6.1.3Polynucleotides6.1.4ADP & ATP6.1.5DNA6.1.6DNA Replication6.1.7RNA6.1.8End of Topic Test - Nucleic Acids & ATP
6.2

Protein Synthesis

6.2.1The Genetic Code6.2.2Polypeptide Synthesis6.2.3RNA Processing in Eukaryotes6.2.4Mutations6.2.5Exam-Style Question - Protein Synthesis6.2.6A-A* (AO2/3) - Coronavirus Translation
7

Transport in Plants

7.1

Transport in Plants

7.1.1Plant Vessels7.1.2Xylem7.1.3Investigating Transpiration7.1.4Adaptations to Water Availability7.1.5Phloem7.1.6End of Topic Test - Transport in Animals & Plants7.1.7A-A* (AO2/3) - Transport in Animals & Plants
8

Transport in Mammals

8.1

Circulatory System

8.1.1Double Circulation8.1.2Blood Vessels8.1.3Important Blood Vessels8.1.4Blood Cells8.1.5Tissue Fluid
8.2

Transport of Oxygen & Carbon Dioxide

8.2.1Haemoglobin8.2.2Oxygen Dissociation
8.3

The Heart

8.3.1Structure of the Heart8.3.2The Cardiac Cycle8.3.3Coordination of Heart Action
9

Gas Exchange

9.1

Gas Exchange System

9.1.1Mammalian Gas Exchange9.1.2Smoking
10

Infectious Diseases

10.1

Infectious Diseases

10.1.1Transmission of Disease10.1.2Tuberculosis10.1.3HIV10.1.4Malaria10.1.5Cholera10.1.6Measles
10.2

Antibiotics

10.2.1Antibiotics
11

Immunity

11.1

The Immune System

11.1.1Phagocytes11.1.2Antigens11.1.3Lymphocytes11.1.4Primary & Secondary Response
11.2

Antibodies & Vaccination

11.2.1Antibodies11.2.2Monoclonal Antibodies11.2.3Immunity11.2.4Vaccines11.2.5Exam-Style Question - Immune System11.2.6A-A* (AO2/3) - Disease & Immune System
12

Energy & Respiration (A2 Only)

12.1

Energy

12.1.1Energy & ATP12.1.2Respiratory Substrates & Quotient12.1.3Respirometers
12.2

Respiration

12.2.1Introduction to Respiration12.2.2Anaerobic Respiration12.2.3Aerobic Respiration12.2.4Chemiosmosis & Coenzymes12.2.5Mitochondria12.2.6Respiration Experiments12.2.7End of Topic Test - Respiration12.2.8A-A* (AO3/4) - Respiration
13

Photosynthesis (A2 Only)

13.1

Photosynthesis

13.1.1Introduction to Photosynthesis13.1.2Light-Dependent Reactions13.1.3Light-Independent Reactions13.1.4Limiting Factors13.1.5Investigating Photosynthesis13.1.6End of Topic Test - Photosynthesis13.1.7A-A* (AO3/4) - Photosynthesis
14

Homeostasis (A2 Only)

14.1

Homeostasis

14.1.1Homeostasis14.1.2Negative Feedback
14.2

The Kidney

14.2.1Kidneys & Osmoregulation
14.3

Cell Signalling

14.3.1Messengers & cAMP
14.4

Blood Glucose Concentration

14.4.1Blood Glucose Concentration14.4.2Controlling Blood Glucose14.4.3Urinalysis
14.5

Homeostasis in Plants

14.5.1Stomata & Guard Cells
15

Control & Coordination (A2 Only)

15.1

Control & Coordination in Mammals

15.1.1Neurones15.1.2Receptors15.1.3Taste15.1.4Reflexes15.1.5Action Potentials15.1.6Saltatory Conduction15.1.7Synapses15.1.8Cholinergic Synnapses15.1.9Neuromuscular Junction15.1.10Skeletal Muscle15.1.11Sliding Filament Theory Contraction15.1.12Sliding Filament Theory Contraction 215.1.13Menstruation15.1.14Contraceptive Pill
15.2

Control & Co-Ordination in Plants

15.2.1Venus Flytrap15.2.2Auixns15.2.3Gibberellins
16

Inherited Change (A2 Only)

16.1

Passage of Information to Offspring

16.1.1Meiosis16.1.2Gametogenesis16.1.3Meiosis & Genetic Diversity
16.2

Genes & Phenotype

16.2.1Key Terms in Genetics16.2.2Inheritance16.2.3Linkage16.2.4Multiple Alleles16.2.5Chi-Squared Test16.2.6Mutations16.2.7Specific Mutations16.2.8End of Topic Test - Genetics16.2.9A-A* (AO2/3) - Genetics
16.3

Gene Control

16.3.1lac Operon16.3.2Transcription Factors16.3.3Gibberellins & DELLA Proteins
17

Selection & Evolution (A2 Only)

17.1

Variation

17.1.1Phenotypic Variation17.1.2Continuous & Discontinuous Variation17.1.3t-Tests
17.2

Natural & Artificial Selection

17.2.1Natural Selection & Evolution17.2.2Types of Selection17.2.3Types of Selection Summary17.2.4Genetic Drift & Founder Effect17.2.5Populations17.2.6Hardy-Weinberg Principle17.2.7Artificial Selection
17.3

Evolution

17.3.1Evolution by Natural Selection17.3.2Evidence for Evolution17.3.3Speciation17.3.4Extinction
18

Classification & Conservation (A2 Only)

18.1

Biodiversity

18.1.1Key Terms18.1.2Biodiversity18.1.3Sampling Methods18.1.4Correlation18.1.5Spearman’s Rank18.1.6Measuring Biodiversity
18.2

Classification

18.2.13-Domain Classification System18.2.2Linnaean Classification System
18.3

Conservation

18.3.1Importance of Biodiversity18.3.2Conservation18.3.3Zoos, Seedbanks, & Other Conservation Methods18.3.4Assisted Reproduction & Contraception18.3.5Non-Governmental Organisations
19

Genetic Technology (A2 Only)

19.1

Manipulating Genomes

19.1.1Recombinant DNA & Genetic Engineering19.1.2Restriction Endonucleases19.1.3Gel Electrophoresis19.1.4DNA Probes & Microarrays19.1.5End of Topic Test - Manipulating Genomes19.1.6A-A* (AO2/3) - Manipulating Genomes
19.2

Genetic Technology Applied to Medicine

19.2.1Bioinformatics19.2.2Applications of Recombinant DNA19.2.3Genetic Screening19.2.4Gene Therapy19.2.5Ethics19.2.6DNA Profiling & Forensics
19.3

Genetically Modified Organisms in Agriculture

19.3.1GM Crops & Livestock19.3.2Ethics

Practice questions on Cell Signalling

Can you answer these? Test yourself with free interactive practice on Seneca — used by over 10 million students.

  1. 1
    Which of the following would be most likely to a membrane-bound receptor?Multiple choice
  2. 2
    Which of the following is a non-polar ligand?Multiple choice
Answer all questions on Cell Signalling

Unlock your full potential with Seneca Premium

  • Unlimited access to 10,000+ open-ended exam questions

  • Mini-mock exams based on your study history

  • Unlock 800+ premium courses & e-books

Get started with Seneca Premium

Fluid Mosaic Model

End of Topic Test - Biological Membranes