What are the three points of the Cell Theory?
- All living things are made of cells
- Cells are the basic unit of life
- All cells come from pre-existing cells
The Cell Theory is fundamental to understanding biology and the structure of living organisms.
Describe the structure of DNA.
Double helix, made of nucleotides (sugar, phosphate, base)
DNA is the hereditary material in all known living organisms.
What are the base pairings in DNA?
- Adenine ↔ Thymine
- Cytosine ↔ Guanine
These pairings are crucial for DNA replication and transcription.
Define the types of mutations.
- Deletion: nucleotide removed
- Insertion: nucleotide added
- Substitution: nucleotide swapped
Mutations can lead to changes in protein synthesis and can affect an organism’s traits.
What is transcription in protein synthesis?
DNA → mRNA
Transcription is the first step in the process of gene expression.
What is translation in protein synthesis?
mRNA → amino acid chain (protein)
Translation occurs in the ribosomes and is essential for protein formation.
What do Punnett Squares predict?
Inheritance of traits (genotype ratios)
Punnett Squares are used in genetics to determine the probability of an offspring inheriting particular traits.
What are the main differences between plant cells and animal cells?
- Plant cells: Cell wall, chloroplasts, large vacuole
- Animal cells: No cell wall, no chloroplasts, small vacuoles
These differences are essential for the functions and characteristics of each cell type.
List the key organelles and their functions.
- Nucleus: controls cell, stores DNA
- Mitochondria: energy (ATP)
- Ribosomes: protein synthesis
- Golgi apparatus: packaging proteins
- Cell membrane: controls entry/exit
Organelles perform specific functions necessary for cell survival and operation.
What are the three lines of defence in immunity?
- Physical barriers (skin, mucus)
- Innate immunity (phagocytes, inflammation)
- Adaptive immunity (B cells, T cells, antibodies)
These lines of defence work together to protect the body from pathogens.
What do vaccines contain?
Antigens → train immune system to recognize pathogens
Vaccines are crucial for preventing infectious diseases.
What is the role of B cells in the immune system?
Produce antibodies
B cells are a key component of the adaptive immune response.
Define antigens.
Molecules on pathogen surface that trigger immune response
Antigens are recognized by the immune system as foreign.
What are the characteristics of bacteria?
- Prokaryotic
- Reproduce by binary fission
- Cause disease by toxins
Bacteria are one of the most common types of pathogens.
What are the characteristics of fungi?
- Eukaryotic
- Reproduce by spores
- Can infect skin/lungs
Fungi can be both beneficial and harmful to humans.
What are the characteristics of viruses?
- Non-living
- Hijack host cells to reproduce
- Cause cell damage
Viruses require a host to replicate and can lead to various diseases.
What are antibacterials/antimicrobials?
Kill or inhibit bacteria (e.g. break cell walls, stop protein synthesis)
These substances are vital in treating bacterial infections.
What are the 5 levels of organisation in biology?
- Cell
- Tissue
- Organ
- Organ system
- Organism
Understanding these levels helps in studying biological systems.
List the structural trends in human evolution.
- Larger brain size
- Smaller jaw/teeth
- Flatter face
- Bipedalism (upright walking)
- Shorter arms, longer legs
- Use of tools/language
These trends highlight the adaptations of humans over time.
What is fossilisation?
Organisms preserved in sediment, amber, ice, etc.
Fossils provide critical evidence for understanding the history of life on Earth.
What is variation in biology?
Differences between individuals in a species
Variation is essential for natural selection and evolution.
What is an example of natural selection?
Peppered moths (industrial revolution changed environment)
This example illustrates how environmental changes can affect species survival.
Define cultural evolution.
Larger brains → language, tools, social learning → faster cultural change
Cultural evolution reflects the development of human societies and knowledge.
What is a nucleotide?
Building block of DNA (sugar + phosphate + base)
Nucleotides are essential for the structure and function of DNA.
