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