Topic 1 Key Concepts in Biology Flashcards
Name the structures found in both animal and plant cells.
Nucleus, cytoplasm, cell membrane, mitochondria, ribosomes.
What additional structures are found in plant cells but not in animal cells?
Cell wall, chloroplasts, and a permanent vacuole
What is the function of the mitochondria?
The site of aerobic respiration, where energy is released from glucose.
What is the function of ribosomes?
To synthesize proteins by joining amino acids together.
What is the formula for magnification?
Magnification = Image size ÷ Actual size.
Which type of microscope has a higher resolution, and why?
Electron microscopes, because they use electron beams that have shorter wavelengths than light, providing more detailed images.
What are the two main types of microscopes used to study cells?
Light microscope and electron microscope.
What is the main disadvantage of electron microscopes compared to light microscopes?
Electron microscopes cannot be used to view living specimens, as the samples must be placed in a vacuum.
What is an enzyme?
A biological catalyst that speeds up chemical reactions in the body without being used up.
What is the active site of an enzyme?
The region on the enzyme where the substrate binds and the reaction takes place.
How does temperature affect enzyme activity?
Increasing temperature increases enzyme activity up to the optimum temperature, but beyond this, the enzyme denatures, reducing its activity.
How does pH affect enzyme activity?
Each enzyme has an optimum pH; deviations from this can cause the enzyme to denature, reducing its activity.
What is diffusion?
The movement of particles from an area of high concentration to an area of low concentration.
What is osmosis?
The movement of water molecules across a partially permeable membrane from a region of higher water concentration to a region of lower water concentration.
What is active transport, and how is it different from diffusion?
Active transport moves particles against the concentration gradient (from low to high concentration), requiring energy from respiration, unlike diffusion.
Give an example of where active transport occurs in plants.
In root hair cells, where minerals are absorbed from the soil.
What are the three main types of biological molecules?
Carbohydrates, proteins, and lipids.
What are carbohydrates made of?
Simple sugars like glucose.
What are proteins made of?
Amino acids.
What is the test for starch?
The iodine test – starch turns iodine from brown/orange to blue-black.
How do you test for glucose in a solution?
By using Benedict’s solution; it turns from blue to brick-red when heated if glucose is present.
What is the structure of DNA?
DNA has a double helix structure made up of two strands of nucleotides.
What are the four bases of DNA, and how do they pair?
Adenine (A) pairs with Thymine (T), and Cytosine (C) pairs with Guanine (G).
What is the role of DNA in a cell?
DNA contains the genetic instructions for the development, functioning, growth, and reproduction of all living organisms.
