Meiosis and Genetics Quiz

Microscopy

• Microscopes are the microbiologist's most basic tool
• Microscopes use lenses to magnify object's images
• Light microscopes (5 types)
• Electron microscopes (2 types)
• Compound light microscopes use visible light to illuminate cells
• Different types include: brightfield, darkfield, phase-contrast, differential interference contrast (DIC) and fluorescence
• Brightfield microscopes visualize specimens because of differences in contrast (density) between the specimen and its surroundings
• Magnification = objective magnification × ocular magnification
• Maximum magnification ~2,000x

Staining

• Dyes are organic compounds that bind to specific cellular materials
• Examples are methylene blue, safranin, and crystal violet
• Differential stains separate bacteria into gram-positive and gram-negative groups
• Gram-positive bacteria appear purple, and gram-negative bacteria appear red after staining

Prokaryotic & Eukaryotic Cells

• All cells are either prokaryotic or eukaryotic
• Prokaryotic cells appeared first and were the only life form on Earth for billions of years
• Prokaryotes are unicellular
• Eukaryotes are much more advanced and can be unicellular or multicellular
• Prokaryotes are simpler than eukaryotes
• Prokaryotic cells have no nuclear membrane, their genetic material is dispersed throughout the cytoplasm
• Prokaryotes do not have membrane-bound organelles
• Prokaryotic cells have a simple internal structure
• Prokaryotic cells are smaller than eukaryotic cells

Cell Components

• The cell is the smallest unit of life
• A cell is the basic unit from which all living organisms are made
• There are many types of cells, some are unicellular, and some are multicellular
• Cell components differ depending on whether the cell is an animal or plant cell.

Cell Division (Mitosis)

• Mitosis produces two daughter cells identical to the parent cell.
• If the parent cell is haploid, the daughters will be also haploid.
• If the parent cell is diploid, the daughters will be also diploid
• It involves the body cells of an organism.
• Includes four stages: interphase, prophase, metaphase, anaphase and telophase
• In interphase, DNA and organelles duplicate.
• Prophase, chromosomes condense, nuclear membrane disintegrates.
• Metaphase, chromosomes align at the equator.
• Anaphase, chromatids separate.
• Telophase, and two nuclei form, and the cell divides into two.

Cell Division (Meiosis)

• Meiosis is a reductive division (reduces number of chromosomes by half)
• Meiosis produces reproductive cells or sex cells
• If the parent cell is diploid, the resulting cells will be haploids
• Meiosis consists of two cell divisions (meiosis I & meiosis II)
• The process leads to four daughter cells each with half the number of chromosomes as the parent cell

Cell Specialization

• Stem cells are unspecialized cells in developing embryos that differentiate into different cell types
• Examples include: red blood cells, nerve cells, muscle cells, and sperm cells
• The structure of each specialized cell is suited to its function and environment
• Red blood cells (RBCs) are small and flexible to squeeze through tiny blood vessels
• Nerve cells have long extensions to transport impulses over longer distances
• Muscle cells are long and have numerous protein fibers that contract and relax to move parts of the body
• Sperm has a streamlined head to move towards the ovum with less friction; and a tail to swim towards the ovum.

Plant Cells (Specialization)

• Unlike animals, many plant cells retain the ability to differentiate and specialize throughout their life
• These cells are found in tissues called meristems
• Root hair cells have a large surface area to absorb water and mineral salts.
• Xylem cells have tough walls filled with lignin to transport water and minerals from roots to leaves.
• Phloem cells transport food made in the leaves to other parts of the plant including roots.
• Palisade cells are elongated so that they can be tightly packed for efficient photosynthesis with lots of chloroplasts to absorb sunlight.
• Guard cells are crescent shaped, are paired to form stomata that regulate the opening & closing of stomata which affects the rate of transpiration.

Movement of Substances

• Diffusion is the passive movement of particles from a high concentration to a lower concentration
• Osmosis is the passive movement of water across a semipermeable membrane from a high water potential to a low water potential
• Active transport moves substances against a concentration gradient using energy from respiration

Kingdoms of Living Things

• Organisms are grouped according to common characteristics
• Classification of organisms is called taxonomy
• Key characteristics are: feeding, structure, reproduction

Viruses

• Viruses are non-living entities because they can only survive and reproduce in living cells.
• Their simple, acellular organization, the absence of both DNA and RNA, and their inability to reproduce independently of cells
• Three main classes: animal viruses, bacterial viruses (bacteriophages), and plant viruses.

Bacteria

• Bacteria are unicellular organisms
• Variety in shapes: cocci (spherical), coccus (plural), bacillus (rod-shaped), streptococci (chain shaped).

Fungi

• Fungi are a kingdom that include unicellular & multicellular species.
• Fungi do not contain chlorophyll, and are heterotrophic, usually saprophytic (obtain food from dead and decaying matter)

Protista

• Protists are a diverse kingdom.
• Some are animal-like (Protozoa), plant-like (Protophyta) or fungus-like.

Animalia (Chordata)

• Vertebrates include fish, birds, amphibians, reptiles, and mammals
• Chordates have these characteristics: have a vertebral column, have an internal skeleton, a hollow nerve tube, a notochord (in some), have a well-developed closed blood system & a tail behind the anus.

The Five Major Kingdoms of Life

• Monera (Bacteria)
• Protista
• Fungi
• Plants
• Animals

The Cell Cycle

• A series of events that takes place in a cell as it grows and divides
• The process that leads from one cell to 2 identical cells.

Blood

• Blood is a tissue with liquid state.
• It circulates through a system that performs the following:
  • Transport nutrients to cells and remove wastes.
  • Regulation of temperature, pH & osmotic pressure
  • Protection/fight infections (white blood cells)
• Composed of 45% cells (red & white blood cells, & platelets) and 55% plasma (water, proteins, nutrients, hormones, dissolved waste).

The Lymphatic System

• Network of lymphatic vessels and lymph nodes maintains homeostasis, return fluid lost from blood vascular system, returns fluids to the blood to maintain the blood volume

Respiration

• Process that releases energy from food molecules
• Two types, aerobic and anaerobic respiration (aerobic respiration requires oxygen to produce energy; anaerobic respiration occurs without oxygen and produces less energy)
• The products of respiration are: water + carbon dioxide + energy