Science Biology Test Review PDF

Chapter 2: Biology Test 2.1 - Plant & Animal Cells Cell Theory All living things are made up of one or more cells + their products The cell is the simplest unit that can carry out all life processes All cells come from other cells; they don’t come from non-living matter Types of...

Chapter 2: Biology Test 2.1 - Plant & Animal Cells Cell Theory All living things are made up of one or more cells + their products The cell is the simplest unit that can carry out all life processes All cells come from other cells; they don’t come from non-living matter Types of Cells: Prokaryotes vs Eukaryotes Prokaryote: A cell without a nucleus or other membrane-bound organelles ○ It is the simplest form of life (ex. Bacteria, E.coli) Eukaryote: A cell that has a nucleus and other organelles, each surrounded by a thin membrane. ○ Eukaryotes w/ one cell: single-celled organisms (ex. Amoeba) ○ Eukaryotes w/ multiple cells: multicellular organisms (ex. Plants & Animals) ○ Complex organisms are made up of Eukaryotic cells Cell Structure/Organelles Cell have organelles (“mini organs”) that perform specific functions for the cell Regular Organelles: ○ Cytoplasm: A jelly-like liquid made of mostly water. (Found In Both) organelles are found within it (suspended in cytoplasm) location of many chemical reactions ○ Cell Membrane: A double layered wall that supports the cell and keeps substances in/out of cell (Found in Both) semi-permeable membrane - allows some small particles to pass, but not larger proteins Membranes are made of lipids (fat) ○ Nucleus: A spherical organelle that contains the DNA(genetic material) and controls all cell activity (Found in Both) DNA (deoxyribonucleic acid) contains all the cell’s genetic info in chromosomes that provide instructions for all cell activity.  during cell division this DNA is copied to each cell ○ Nucleolus: Produces ribosomes in the nucleus (Found in Both) ○ Mitochondria: Use enzymes to make energy(ATP) for the cell using cellular respiration. (Found in Both) Active cells (ex.muscle cells) have more mitochondria than inactive cells (ex.fat cells) because they need more energy ○ Ribosomes: Site of protein production/synthesis. (Found in Both) ○ Endoplasmic Reticulum: A 3D network of branching tubes + pockets used to transport materials through the cell. (Found in Both) Connect nuclear membrane to cell membrane by weaving through cytoplasm. ○ Golgi Bodies: Collects + processes materials to be removed from cell. It can make and secrete mucus. (Found in Both) ○ Vacuoles: A single layer membrane filled with fluids + other substances (Found in Both) Store and remove substances, maintain turgor pressure (fluid pressure) + engulf substances for digestion Store nutrients and wastes (“storage sacs”) Animal cells have many tiny vacuoles and plant cells have one large central vacuole ○ Lysosome: Contains enzymes that digest unwanted substances (Found in Animal) ○ Cilia: “Little Hairs”, Their movement helps move things (ex. In respiratory tract beat upwards to remove dust/particles) (Found in Animals) ○ Flagella: Whip-like tail that helps cells move (e.g sperm, bacteria.) (Found in Animals) ○ Centrioles: Help with spindle fiber formation which are required for cell division (Found in Animals) ○ Nuclear Membrane: A membrane that protects and separates the nucleus of a cell from the cytoplasm. The nuclear membrane, just like the plasma membrane, is composed of a phospholipid layer. (In both?) Organelles in Plants Cells: Plant cells have a few unique structures but are have many common organelles with animal cells ○ Vacuole: Plants have one large vacuole to provide structure for plant ○ Cell Wall: Located outside cell membrane, rigid; made of cellulose, provides support and protection from injury  ○ Chloroplasts: Contain chlorophyll used in photosynthesis Cellular Respiration & Photosynthesis Cellular respiration is how living things use oxygen to break down food and obtain energy for their cells to work. ○ Glucose + Oxygen → Carbon Dioxide + Water + Energy ○ C6H12O6 + 6O2 → 6CO2 + 6H2O + ATP Photosynthesis is the process by which plants use sunlight, water, and carbon dioxide to create oxygen and energy in the form of sugar ○ Carbon Dioxide + Water + Sunlight→ Glucose + Oxygen + Energy ○ 6CO2 + 6H2O + Sunlight → C6H12O6 + 6O2 + ATP They are OPPOSITE to each/other Plants vs Animal Cells Cell Wall: Plant cells have a rigid cell wall made of cellulose that provides structure and support, whereas animal cells don’t have one but have a flexible cell membrane. Chloroplasts: Plant cells have chloroplasts, which are responsible for Photosynthesis, allowing them to convert sunlight into energy. Animal cells don’t, and rely on other methods, like consuming food, to get energy. Vacuoles: Plant cells typically have 1 large central vacuole that stores water, nutrients, and waste products, maintaining cell turgor. Animal cells have smaller vacuoles, but they are not as important/central to cell function. Shape: Plant cells are generally more rectangular due to the rigid cell wall giving them a fixed shape. Animal cells have a more variable and rounded shape due to not having a cell wall, allowing for greater flexibility. 2.3- The Important of Cell Division Cell Division: Allows organisms to reproduce, to grow, and repair damage (regeneration) Cell Division for Reproduction  All cells, including single-celled organisms use cell division to reproduce. In reproduction a new cell is created w/ a complete set of genetic info. The two type of reproduction are asexual and sexual reproduction: ○ Asexual Reproduction: the process of producing genetically identical offspring from one parent (ex. bacteria) ○ Sexual Production: the process of producing offspring by the fusion of two gametes. The offspring have genetic info from both parents (ex. Plants & Animals) A cell from one parent (gamete) joins with a cell from another parents These two gametes are different from other body cells because they only have half the DNA usually found in a cell When the two gametes combine, the offspring inherits genetic info from both parents Cell Division for Growth All organisms need to grow. As multicellular organisms grow, the # cells increase, but why don’t cells just increase in size instead? Cell Transport ○ All cells need chemical to move efficiently around the cell to undergo reactions ○ These chemicals are used for all cell activity & growth ○ Waste products and CO2 must also diffuse out of the cell quickly so they don’t poison the cell. How do chemicals move around the cell? ○ Diffusion: Chemicals in a cell move from an area of high concentration to lower concentration ○ Concentration: The amount of solute present in a given volume of solution ○ Osmosis: Water enters + leaves the cell by moving from an area with higher concentration of water to an area with a lower concentration of water. (diffusion) Diffusion is a passive action (the organisms doesn’t use any ATP) In order for diffusion & osmosis to work effectively, the cell size can’t get too big, because otherwise the movement of water and chemicals will slow down/be too slow When a multicellular organism needs to grow, it will undergo cell division instead of getting bigger cells for this reason Cell Division for Repair  Cells are living organisms and like all living things they have a limited life span. Since they are constantly dying they need to be replaced through cell division. Examples: ○ Red Blood Cells: 120 days ○ Skin Cells: 30 days ○ Stomach Lining: 2 days ○ Never Cells: Long Living (no cell division) ○ Break a Bone: Cells divide to heal the break 2.5 - The Cell Cycle The Cell Cycle: The repeating cycle of events in the life of a cell The Cell Cycle has 4 phases: Interphase ○ G1 Phase - cell growth  ○ S Phase - DNA replication ○ G2 Phase - preparation for mitosis Mitosis Chromosomes Every cell contains chromosomes Chromosomes are long pieces of coiled DNA and proteins that contain genetic info Chromosomes are only visible when the cell is dividing (prophase: start of mitosis) When the cell is not dividing the DNA and proteins are spread throughout the cell as chromatin. ○ Chromatin refers to a mixture of DNA and proteins that form the chromosomes found in the cells of humans and other higher organisms. At the start of cell division, chromosomes condense into visible structures Before cell division can happens, each chromosome is copied so that each chromosome consists of two identical sister chromatids ○ A chromatid is one of the two identical halves of a chromosome that has been replicated in preparation for cell division When cells divide, one chromatid goes to each of the two new cells so each has a complete copy Interphase ○ A cell spends around 90% of its time in interphase ○ During interphase, the cell takes in nutrients, grows and conducts other normal cell functions except cell division First Growth Phase (G1) ○ The G1 phase is a period of growth for the cell ○ During this phase new proteins & organelles are produced Synthesis Phase (S) ○ During the S phase, the cells makes (synthesizes) an entire copy of the DNA of the cell Second Growth Phase (G2) ○ During this phase the cell produces the organelles and structures needed for cell division The G2 phases is the shortest part of interphase Cell Division  Once the cell is ready to divide and make 2 new identical cells, it enters Mitosis (M phase) During the M Phase, all of the cell’s energy is devoted to cell division Mitosis has four phases (PMAT): prophase, metaphase, anaphase, and telophase ○ Mitosis is followed by Cytokinesis Mitosis: Division of the nucleus Cytokinesis: Division of the cytoplasm At the end of telophase and cytokinesis, 2 daughter cells are formed, each containing identical genetic info Prophase ○ During this, the chromatin (DNA + proteins) that makes up chromosomes condenses ○ The DNA has already been replicated, so the chromosomes contain 2 identical sister chromatids held together by a centromere Centromere: the region of the chromosome to which the spindle fiber is attached during cell division ○ During prophase, the nuclear membrane disappears Metaphase ○ During this, the chromosomes line up in the middle of the cell ○ Spindle fibers extend from the poles of the cell and attach to the centromeres (center) of each chromosome Spindle Fiber: a network of filaments that are formed during the cell division process ,help in the movement of chromosomes during both mitosis. Anaphase ○ During this, the sister chromatids separate at the centromere and are called “daughter chromosomes” ○ The separates chromosomes are pulled to opposite ends of the cell Telophase ○ During this, the chromosomes are no longer visible and become chromatin ○ A nuclear membrane forms around each group of daughter chromosomes The cell appears to have 2 nuclei (nucleuses) Cytokinesis ○ During cytokinesis, the cell divides the cytoplasm into two portions ○ 2 identical daughter cells are produced Animal cells: cell pinches in center  Plant cells: a plate develops in between that becomes the cell wall A cell will remain in Interphase and not divide if ○ Signals from surrounding cells tell it not to ○ There are not enough nutrient ○ The DNA has not been replicated ○ The DNA is damaged Cell Death The cell cycle regulates the lifespan of a cell Sometimes cells die because they have suffered irreparable injury/damage Apoptosis A cell also dies when it is no longer needed or no longer useful to the organism This regulated/controlled cell death is called Apoptosis 2.7 - Cell Division Gone Wrong: Cancer What is Cancer? ○ A cancer cell continues to divide despite messages from the nucleus or surrounding cells that tell it to stop. ○ Cancers occur in cells that are rapidly dividing such as skin, lung, breast and the cells that line the intestinal tract. Cancer Occurs due to an Accumulation of Mutations  ○ When cells divide, random changes can occur, known as mutations. ○ Sometimes mutations occur in DNA that controls cell division ○ Some scientists suggest at least 7 mutations are required to make a normal cell a cancer cell Mutagens & Carcinogens ○ A mutagen is a substance/agent that induces/triggers heritable change in cells or organism ○ A carcinogen is a substance that induces unregulated growth processes in cells/tissues of multicellular animals, leading to cancer. Some mutagens are carcinogens but not all. Sometimes change is good. Some well known carcinogens area X-rays UV rays Smoking Organic Solvent Cancer Causes Include: Mutation, Carcinogens, and Genetics A benign tumor is non-cancerous, grows slowly, stays localized, and doesn’t spread, making it generally less harmful. A malignant tumor is cancerous, grows quickly, invades nearby tissues, and can spread to other parts of the body, posing a serious health risk. Steps in Tumor Formation ○ Step 1. The primary tumor develops as a group of cells that are growing out of control. ○ Step 2. The tumor gets bigger and stimulates blood vessels to supply it from the surrounding tissues. ○ Step 3. Tumor cells squeeze into blood and lymph vessels and move to other parts of the body. This is called metastasis. ○ Step 4. When the tumor cells reach other areas of the body, like the liver and lungs, they begin to grow and form secondary tumors. If they are not treated quickly enough, the damage that these secondary tumors cause can be fatal. 1. Prevention: Cancer Screening Checking for cancer even if there are no symptoms  Pap Test - checks for cervical cancer ○ starts around age 18 Breast self-examination Testicular self-examination PSA test - For prostate cancer Mole Observation ○ ABCD: Asymmetry, Border, Colour, Diameter Reducing your risk Lifestyle Choices ○ Avoid smoking, Healthy diet, Exercise 2. Diagnosis Imaging Colonoscopy - Endoscopy of the colon X-ray MRI Ultrasound CT/CAT Scan Examining cells Obtained if medical tests show any abnormalities Blood or a sample of tumor cells is removed surgically and examined under a microscope. 3. Treatment Options Depends on the type of cancer. Most commonly chemotherapy, radiation, surgery, or a combination of those. Chemotherapy Cancer cells grow in an uncontrolled way. Chemotherapy drugs slow/even stop the cancer cells from growing, multiplying, or spreading to other parts of your body. Chemotherapy is powerful,l affecting the whole body, so healthy cells can also be damaged. This damage to healthy cells causes side effects. The damage is mostly temporary, and the healthy cells will repair themselves. Radiation  Is the use of a certain type of energy (radiation) from x-rays or gamma rays, to destroy cancer cells. Radiation in high doses targets cells in the area being treated by damaging the DNA in their genes, making it impossible for them to grow + divide. During radiation therapy, both cancer cells (which are growing in an uncontrolled way) and healthy cells are affected, but most healthy cells can repair themselves afterwards Biophotonics Uses light beams to detect and treat cancer Very sensitive Pioneered at the University of Toronto Fewer side effects than radiation. The goals of therapy are to: Destroy the cancer ○ Chemotherapy, by itself or with another treatment, is given to destroy cancer cells in the body. Shrink a tumor before other treatments ○ Sometimes chemotherapy is given to shrink a tumor before surgery or radiation therapy Destroy cancer cells after other treatments ○ Chemotherapy is often given in addition to surgery or radiation treatment to destroy cancer cells that may have been missed by the surgery or radiation. 2.9 - Specialized Cells A specialized cell has unique features so that it can perform specific functions and comes from non-specialized cells (in a process called cellular differentiation/specialization) ○ Cells that have differentiated from each other are called specialized cells ○ When damaged they cannot perform their specific functions Specialized Plant Cells  Plants also have specialized cells that help do specific functions ○ Chloroplasts are specialized cells that perform photosynthesis just below the surface of leaves whereas other cells are specialized to absorb water Come from non-specialized cells through cellular differentiation. Types of Specialized in Animals Red Blood Cells: Contain hemoglobin that carries oxygen in the blood, are smooth so that they can easily pass through the blood vessel Skin Cells: Fit together tightly to cover the outside of the body, protect the cells insides and reduces water loss Bone Cells: Collect calcium from food, allow growth and repair of bones White Blood Cells: Can move like an amoeba to engulf bacteria and fight infection Sperm Cells: Are able to move independently, carry DNA from the male parent to join an egg from the female parent Fat Cells: Have a large vacuole in which to store fat molecules, how cells store chemical energy Nerve Cells: Are long, thin, and have many branches, conduct electrical impulses to coordinate body activity. Photophore Cells: Can emit light, are used by animals that are active at night or live in the deep ocean Muscle Cells: Are arranged in bundles called muscle fibers, can contract which makes the fibers shorters and causes bones to move Goblet Cells: Help keep dirt out of lungs, orange cells secrete mucus, green grassy stuff are cilia. The cilia can move mucus along the trachea to trap and remove any inhaled dust/dirt Types of Specialized in Animals Photosynthetic Cells: Contain many chloroplasts to collect energy from sunlight to make sugar for the plant Guard Cells: Control water loss in the surface of leaves Epidermal Cells: On young roots have hairs that absorb water from the soil Storage Cells: Contain special structures that store starch, a source of energy for the plant Xylem Cells: Transport water and dissolved mineral throughout the plant Phloem Cells: Transport dissolved sugars around the plant