Plant Tropism and Eye Structure Quiz

Tropism

• Tropism is directional growth or movement of an organism in response to environmental stimuli
• Plants commonly exhibit tropism in response to stimuli like light (phototropism), gravity (gravitropism), and water (hydrotropism)
• Tropism can also describe the behavior of viruses or pathogens targeting specific host tissues

Structure of the Eye

• The human eye is a complex sensory organ for vision
• Key structures:
  • Cornea: refracts light entering the eye
  • Iris: controls pupil size and light entry
  • Pupil: opening in the iris for light
  • Lens: adjusts shape to focus light
  • Retina: contains photoreceptor cells (rods and cones) converting light into electrical impulses
  • Optic Nerve: transmits visual information to the brain

Function of Auxin

• Auxin is a plant hormone crucial for growth regulation
• Auxin influences processes like:
  • Cell elongation: loosens cell walls
  • Apical dominance: suppresses lateral bud growth, making plants taller
  • Tropisms: mediates responses to light and gravity by redistributing itself within tissues leading to differential growth rates

Feedback Mechanisms

• Feedback mechanism: a biological process where the output of a system influences its own activity
• Two main types of feedback:
  • Positive feedback: enhances or amplifies change (e.g., childbirth)
  • Negative feedback: reduces or dampens change, maintaining homeostasis (e.g., body temperature regulation)

Inheritance of Genes

• Inheritance: genetic transmission of traits from parents to offspring
• Genes are segments of DNA that determine specific characteristics
• Gregor Mendel's studies on pea plants established fundamental concepts like dominant and recessive traits

Offspring

• Offspring are descendants produced by reproduction
• Sexual reproduction results in offspring inheriting genetic material from both parents, leading to genetic variation
• Asexual reproduction results in offspring genetically identical to the parent

Punnett Square

• Punnett square: graphical tool used to predict genotypic and phenotypic outcomes of genetic crosses
• Visualises how alleles from each parent combine during fertilization

Natural Selection

• Natural selection: a fundamental mechanism of evolution proposed by Charles Darwin
• Explains how individuals with advantageous traits are more likely to survive and reproduce, leading to adaptations within populations over time

Reproduction in Plants and Animals

• Reproduction: the biological process of creating new organisms
• Two main types:
  • Asexual reproduction: involves a single parent producing genetically identical offspring (e.g., budding)
  • Sexual reproduction: involves two parents contributing genetic material to produce genetically diverse offspring

Negative Feedback Loops

• Negative feedback loop: a control mechanism that counteracts changes in a system (e.g., sweating when body temperature rises)
• Helps maintain stable internal conditions despite external fluctuations

Test your knowledge on tropism in plants and the anatomy of the human eye. This quiz covers key concepts such as phototropism, gravitropism, and the structure and function of various eye components. Additionally, explore the role of auxin in plant growth regulation.