Biology January Exam - Grade 11, Semester 1

The actual size of an object in real life.

The magnified size of an object as seen through a microscope.

The ratio between the actual size of an object and its image size in a microscope.

A scale used to measure the size of things seen through a microscope's eyepiece.

A ruler with precise markings used to calibrate the eyepiece graticule.

The process of relating the divisions on the eyepiece graticule to actual measurements.

Measuring the length or width of an object using the eyepiece graticule.

The use of appropriate units (mm, um, nm) to express measurements based on the size of the objects.

The process of creating a temporary slide to observe cells under a light microscope. It involves collecting the sample, placing it on the slide, adding stain (optional), adding a coverslip, removing excess liquid, and examining it under the microscope.

A drawing of a cell observed under a light microscope or from a photomicrograph, emphasizing important structures and organelles. It involves accurate outlining, labeling, keeping it simple, and indicating the magnification.

A process of calculating the actual size of a specimen from a scale drawing, photomicrograph, or electron micrograph using the magnification and image size. It involves applying the formula: Actual size = Image size / Magnification.

A special type of microscopy that uses a beam of electrons to create a highly magnified image of a specimen. It provides detailed information about the internal structures of cells and organelles.

A type of electron microscopy where the electron beam scans the surface of a specimen, creating a 3D image with high resolution. It's useful for observing surface details and structures.

A type of electron microscopy where the electron beam passes through a very thin specimen, generating a 2D image of the internal structures. It provides detailed information about the internal organization of cells and organelles.

A thin, flexible layer surrounding the cell, made of phospholipids and proteins.

A large, round structure containing DNA (genetic material), surrounded by a double membrane. It also contains a nucleolus.

A stack of flattened sacs that modify and package proteins into vesicles for transport within or out of the cell.

Rod-shaped organelles with a double membrane, containing folded inner membranes called cristae. They are the sites of aerobic respiration, where energy is produced in the form of ATP.

Small, cylindrical structures found in animal cells only, composed of microtubules. They are involved in cell division.

Oval-shaped organelles found in plant cells, containing chlorophyll. They are the sites of photosynthesis, where sunlight is converted into energy.

A rigid structure outside the cell membrane, made of cellulose (in plants) and provides support and shape to the cell.

A large, central sac in plant cells surrounded by a membrane called the tonoplast. It stores water, nutrients, and waste, and helps maintain cell shape.

The maximum rate at which an enzyme can work when all its active sites are fully occupied by the substrate.

The substrate concentration at which the enzyme works at half its maximum rate (Vmax).

A low Km indicates a strong affinity between the enzyme and substrate, meaning the enzyme binds easily to the substrate.

A high Km indicates a weak affinity between the enzyme and substrate, meaning the enzyme doesn't bind easily to the substrate.

These inhibitors bind to the enzyme's active site, preventing the substrate from binding and slowing down the reaction.

These inhibitors bind to a different site on the enzyme, changing its shape and reducing its activity. Adding more substrate won't help.

Enzyme is trapped in alginate beads, allowing substrate to reach and react, while the enzyme stays in place for reuse.

Immobilized enzymes are reusable, efficient, and can be easily separated from the reaction mixture.

The enzyme is free to move in the solution, and the substrate reacts with it. The enzyme can be washed away after the reaction is complete.

Immobilized enzymes can be used many times.

It's easy to separate the enzyme from the product after the reaction.

Immobilized enzymes can handle changes in temperature and pH better.

Immobilized enzymes are useful in continuous processes, where the reaction goes on without stopping.

A chromosome is made of two identical copies called sister chromatids, joined together at the centromere.

The centromere is the region where the sister chromatids are held together; it attaches to spindle fibers during cell division.

Telomeres protect the chromosome from damage and prevent it from sticking to other chromosomes.

Continuous cell division due to errors in cell cycle control, resulting in a mass of abnormal cells.

A localized mass of abnormal cells that may be benign or malignant.

Non-cancerous tumors that do not spread to other parts of the body.

Cancerous tumors that invade surrounding tissues and can spread to other parts of the body.

The first stage of mitosis, where chromosomes condense, the nuclear envelope breaks down, and spindle fibers form.

The second stage of mitosis, where chromosomes line up at the equator of the cell and spindle fibers attach to centromeres.

The third stage of mitosis, where sister chromatids are pulled apart to opposite poles by spindle fibers.

The final stage of mitosis, where chromosomes decondense, nuclear envelopes reform, and spindle fibers disappear.