Biology January Exam - Grade 11, Semester 1

The stain enhances the visibility of cellular structures.

Observe, use pencil only, outline clearly, label accurately, and keep it simple.

Magnification = Image size / Actual size.

<p>Starting with low magnification allows better orientation and locating of the specimen.</p> Signup and view all the answers

<p>Gently place the coverslip at an angle.</p> Signup and view all the answers

<p>You should label the cell membrane, nucleus, cytoplasm, and cell wall if present.</p> Signup and view all the answers

<p>Pencil is recommended for clarity and neatness of lines.</p> Signup and view all the answers

<p>Simplicity ensures clarity, while proportionate drawings accurately represent the specimen's dimensions.</p> Signup and view all the answers

<p>Inhibitors slow down the reaction by preventing the enzyme from functioning properly.</p> Signup and view all the answers

<p>Vmax represents the fastest rate an enzyme can work when all active sites are occupied by substrate.</p> Signup and view all the answers

<p>A low Km value indicates a high affinity, meaning the enzyme binds to the substrate easily.</p> Signup and view all the answers

<p>Competitive inhibitors resemble the substrate and compete for the active site, while non-competitive inhibitors bind elsewhere, altering enzyme shape.</p> Signup and view all the answers

<p>Km is determined at the substrate concentration where the enzyme reaches half of its Vmax, allowing comparison of binding efficiency.</p> Signup and view all the answers

<p>Immobilized enzymes can be reused multiple times and are retained in place, allowing for efficient substrate access.</p> Signup and view all the answers

<p>Adding more substrate can help restore the enzyme's activity by outcompeting the inhibitor.</p> Signup and view all the answers

<p>Non-competitive inhibitors decrease enzyme activity by changing its shape, rendering the substrate ineffective.</p> Signup and view all the answers

<p>It controls the entry and exit of substances.</p> Signup and view all the answers

<p>The nucleus is a large, round structure that stores genetic material (DNA) and controls cell activities.</p> Signup and view all the answers

<p>The Golgi apparatus consists of a stack of flattened sacs; it modifies and packages proteins into vesicles for transport.</p> Signup and view all the answers

<p>Mitochondria are rod-shaped with a double membrane and are the site of aerobic respiration, producing ATP.</p> Signup and view all the answers

<p>Centrioles are small cylindrical structures made of microtubules, involved in cell division.</p> Signup and view all the answers

<p>Chloroplasts are oval-shaped with a double membrane; they are the site of photosynthesis and contain chlorophyll.</p> Signup and view all the answers

<p>The cell wall is a rigid structure made of cellulose that provides support and shape to plant cells.</p> Signup and view all the answers

<p>The tonoplast is a membrane surrounding the large central vacuole, which stores water, nutrients, and waste, helping to maintain cell shape.</p> Signup and view all the answers

<p>Enzymes catalyze biochemical reactions by lowering the activation energy needed, allowing substrates to react more efficiently.</p> Signup and view all the answers

<p>Immobilized enzymes can be reused multiple times in continuous processes, facilitating ongoing reactions without interruptions.</p> Signup and view all the answers

<p>A chromosome consists of coiled DNA wrapped around histone proteins, forming a compact structure that includes sister chromatids connected at the centromere.</p> Signup and view all the answers

<p>Telomeres protect the ends of chromosomes from damage and prevent them from fusing with other chromosomes.</p> Signup and view all the answers

<p>Mitosis enables growth by increasing the number of cells, leading to the development of tissues and organs.</p> Signup and view all the answers

<p>Mitosis produces new, genetically identical cells that replace old or damaged cells in tissues.</p> Signup and view all the answers

<p>During asexual reproduction, mitosis produces offspring that are genetically identical to the parent organism.</p> Signup and view all the answers

<p>Sister chromatids are held together at the centromere and are separated during cell division to ensure each daughter cell receives an identical set of chromosomes.</p> Signup and view all the answers

<p>Actual Size = Image Size / Magnification</p> Signup and view all the answers

<p>1 mm = 100 µm</p> Signup and view all the answers

<p>Scanning Electron Micrograph (SEM) shows 3D surface structures, while Transmission Electron Micrograph (TEM) shows detailed internal structures.</p> Signup and view all the answers

<p>Calibration ensures accurate measurements by determining how much each division on the eyepiece graticule represents.</p> Signup and view all the answers

<p>A stage micrometer provides a known scale for calibrating the eyepiece graticule and measuring specimens.</p> Signup and view all the answers

<p>Micrometers (µm) should be used for measuring medium-sized objects such as cells.</p> Signup and view all the answers

<p>The total length is 50 µm.</p> Signup and view all the answers

<p>1 µm = 1,000 nm.</p> Signup and view all the answers

<p>A tumor is a mass of abnormal cells that forms when cell division occurs uncontrollably due to mutations or damaged DNA.</p> Signup and view all the answers

<p>Benign tumors do not spread to other parts of the body, whereas malignant tumors can invade surrounding tissues and spread.</p> Signup and view all the answers

<p>During prophase, chromosomes condense and become visible, the nuclear envelope breaks down, and spindle fibers begin to form.</p> Signup and view all the answers

<p>Spindle fibers attach to the centromeres of chromosomes and help line them up at the cell's equator for proper separation.</p> Signup and view all the answers

<p>Sister chromatids are pulled apart to opposite poles of the cell by spindle fibers, becoming separate chromosomes.</p> Signup and view all the answers

<p>During telophase, chromosomes decondense and become invisible, the nuclear envelope reforms around each set of chromosomes, and spindle fibers disappear.</p> Signup and view all the answers

<p>In metaphase, chromosomes are lined up in the center (equator) of the cell, and spindle fibers are seen attached to the centromeres.</p> Signup and view all the answers

<p>The final process is cytokinesis, where the cytoplasm divides; in animal cells, the membrane pinches in, while in plant cells, a cell plate forms between the new cells.</p> Signup and view all the answers

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.