Lucent Flashcards
What is the definition of living organisms?
Living organisms cannot be defined precisely but are characterized by certain features.
List the four key characteristics that distinguish living organisms from non-living ones.
- Growth
- Reproduction
- Metabolism
- Response to stimuli
What is growth in living organisms?
Increase in the number of cells or mass.
What does reproduction entail in living organisms?
Producing young ones of the same kind.
Define metabolism in the context of living cells.
Chemical reactions occurring inside a living cell.
What is the response to stimuli in living organisms?
The ability to sense and react to environmental conditions.
What are sesmonastic movements?
Movements in response to touch, such as in the ‘Touch me not’ plant.
Who proved that life on Earth originated by chemosynthesis?
Scientist Miller.
What did J.B.S. Haldane suggest about the development of life?
Life must have developed from simple inorganic molecules.
What is the purpose of classification in biology?
To categorize organisms into different groups for study.
Who is known as the ‘Father of Taxonomy’?
Linnaeus.
What are the two kingdoms proposed by Linnaeus?
- Plantae
- Animalia
What did H. Whittaker propose in 1969 regarding classification?
The Five Kingdom Classification.
List the five kingdoms in Whittaker’s classification.
- Monera
- Protista
- Fungi
- Plantae
- Animalia
What does the kingdom Monera include?
All prokaryotic organisms like bacteria.
What are the two groups of bacteria?
- Archaebacteria
- Eubacteria
What are cyanobacteria also known as?
Blue-green algae.
What role do chemosynthetic bacteria play?
Recycling nitrogen, phosphorus, iron, and sulfur.
What is the primary method of reproduction in bacteria?
Fission.
What is the smallest known organism that lacks a cell wall?
Mycoplasma.
What is the basic unit of biological classification?
Species.
What is the highest unit of classification?
Kingdom.
What is binomial nomenclature?
A two-name system for naming organisms.
Provide the scientific name for humans.
Homo sapiens.
What does the study of cell structure and function refer to?
Cytology.
Who coined the term ‘cell’?
Robert Hooke.
What is the smallest cell known?
Mycoplasma gallisepticum.
What is the longest cell in the human body?
Neuron.
What established the cell theory?
Schlieden and Schwann.
List the main features of cell theory.
- All organisms are composed of cells.
- The body of every organism is made of cells.
- Each cell arises from pre-existing cells.
- Every organism starts its life from a single cell.
Differentiate between prokaryotic and eukaryotic cells.
- Prokaryotic cells lack a nucleus and membrane-bound organelles.
- Eukaryotic cells have a nucleus and membrane-bound organelles.
What is the function of mitochondria?
Site of cellular respiration and ATP synthesis.
What do Golgi bodies do?
Storage, processing, and packaging of materials.
What is the role of ribosomes?
Protein synthesis.
What are lysosomes known as and why?
Suicidal bags of the cell due to their role in intracellular digestion.
What is the function of chloroplasts?
Photosynthesis.
What is a vacuole?
Fluid-filled organelle that helps in osmoregulation.
What is the central structure of a cell that controls activities?
Nucleus.
True or False: Eukaryotic cells contain circular DNA.
False. Eukaryotic cells contain linear DNA.
What role does the vacuole play in plant cells?
It helps in osmoregulation and provides turgidity and rigidity
Vacuoles may occupy 90% of total cell volume in plant cells.
What is the nucleus and where is it located in a plant cell?
A spherical, centrally located structure, shifted towards the periphery in plant cells
It is bounded by a double-layered nuclear membrane with pores.
What are the main components found within the nucleoplasm?
Nucleolus and chromatin material
Nucleolus is rich in protein and RNA.
What is chromatin made up of?
DNA and histone protein
Chromatin forms chromosomes during cell division.
What is the function of DNA found in mitochondria and chloroplast?
They are self-replicating organelles capable of producing their own protein.
What is active transport?
The movement of substances against a diffusion gradient using energy from respiration.
What organelles make up the endomembrane system of the cell?
Endoplasmic reticulum, Golgi complex, lysosomes, and vacuoles.
What are the main differences between plant and animal cells?
Plant cells have a cell wall, plastids, and larger vacuoles; animal cells have centrosomes and smaller vacuoles.
What happens to a cell when placed in a hypotonic solution?
It increases in volume.
What are chromosomes made of?
DNA and protein.
What is the term for a pair of chromosomes having the same size and shape?
Homologous chromosomes.
What is the basic unit of heredity?
Gene.
What is a mutation?
Any change in the base sequence within a gene.
What is the difference between diploid and haploid?
Diploid has two complete sets of chromosomes; haploid has one set.
What are the types of RNA and their functions?
- mRNA: Carries messages from DNA to cytoplasm
- rRNA: Site of protein synthesis
- tRNA: Transfers amino acids to ribosome.
What is the process of copying genetic information from DNA into mRNA called?
Transcription.
What is the significance of meiosis?
It creates genetic diversity and produces haploid gametes.
What is karyokinesis?
Division of the nucleus during cell division.
What is the law of segregation?
In the F1 generation, both characters governed by genes are separated.
What is linkage in genetics?
When two different genes on the same chromosome express together instead of independently.
What is cloning?
Producing identical organisms from a single cell with the same genetic character.
What is a genetically modified organism (GMO)?
An organism with manipulated genes to obtain desired traits.
What is the genome?
All genes present in a haploid cell.
What is the difference between DNA and RNA?
DNA is double-stranded with deoxyribose; RNA is single-stranded with ribose.
What is a ribozyme?
An RNA molecule that acts as an enzyme.
What is the term for the potential ability of a plant cell to grow into a complete plant?
Totipotency.
What are autosomes?
Chromosomes responsible for characters other than sex.
What is the chromosomal theory of inheritance?
The theory that genes are located on chromosomes, proposed by Sutton & Boveri.
What is the sex chromosome composition in humans?
Males have XY; females have XX.
What is the significance of the Cas9 protein?
It is used in targeted gene editing.
Where are mitochondria found and how are they inherited?
Found in the mitochondria and inherited via egg cytoplasm
Mitochondria are inherited maternally.
What is mitochondrial replacement therapy?
A method to prevent passing on mitochondrial diseases from parent to child either before or after in-vitro fertilization
This therapy aims to eliminate mitochondrial diseases by replacing defective mitochondria with healthy ones.