Cells Flashcards
Cell Theory
- All living things are made up of one or more cells
- The cell is the simplest unit of life
- All cells come from other cells-they do not come from non-living matte
2 types of cells
Eukaryotes: with a nucleus
And
Prokaryotes: without a nucleus
Organelles
• “little organs”
• Cells have specialized parts that carry out specific functions
• Cells have many types of organelles that all work together
-Some are found ONLY in animal and plant cells
Cytoplasm (in both plant and animal cells)
• Aqueous (water-based) solution inside the cell
• Organelles are suspended in here
Cell Membrane (in both plant and animal cells)
• A thin, double layered film that separates the interior of the cell from the external environment
• Supports the cell and controls movement in and out of the call(‘semi permeable)
Nucleus (in both plant and animal cells)
• “control centre”- directs all cell’s activities
• contains the cell’s DNA (genetic information) on chromosomes
Mitochondria (in both plant and animal cells)
• produce energy for the cell via cellular respiration
Formula: glucose + oxygen ~ carbon dioxide + water + usable energy (Cellular Respiration(opposite of photosynthesis))
• have an inner and outer membrane
• cells that require lots of energy (ex.muscle cells) will have more mitochondria
Endoplasmic Reticulum (in both plant and animal cells)
• system of tubes and canals around the nucleus
• transport materials (ex.proteins and lipids(fat)) through cells
Golgi Apparatus (in both plant and animal cells)
•several tubes- look like a stack of flattened balloons
• packages materials to be removed from cell
• secretes mucus
Vacuoles (in both plant and animal cells)
• membrane bound sacs filled with a watery solution
• Animal Cells: Have many small vacuoles
• Plant Cells: Have one large vacuole
Cell wall
• plant cell only
• tough, rigid layer that surround cell- made of cellulose
• provides support and structure
Chloroplasts
• only in plant cells
• contains all the chemicals (chlorophyll) for photosynthesis
Formula: carbon dioxide + water + energy(light) = glucose + oxygen (Cellular photosynthesis (opposite of respiration))
• plant cells will then use mitochondria to produce usable energy
Lysosomes
• only in animal cells
• contain proteins that can break down molecules (ex. food brought in from extracellular space or bacteria/viruses)
• they are like a garbage dump for a cell
Two types of reproduction(1)
Asexual Reproduction:
• involves only ONE parent
• the offspring are identical to the parent
Two types of reproduction(2)
Sexual Reproduction:
• involves TWO parents
• offspring have characteristics of both parents
• every human call has 46 chromosomes
• one special “Half Cell” from each parent combines to make a new cell
Half Cells
•contains 23 chromosomes
• called gametes
• 2 gametes combine to make 1 cell with a full set of chromosomes
• this is why offspring have characteristics of both parents
2 processes all cells must do
- Aquire Nutrients
- Remove Waste
-chemicals and water must pass the cell membrane to get in or out
-these are moved in and out of the call by Diffusion and Osmosis
-small + uncharged molecules
Diffusion
Chemicals move from an area of high concentration to an area of low concentration (no energy required)
Osmosis
Water moves in the direction which has a greater concentration of solutes ( less concentrated ~ more concentrated, solute hinders the passage of water molecules)
Why must cells divide?
Overtime, you can’t supply nutrients or remove wastes from all parts of the cell fast enough to meet its needs
Cell Cycle: Stage 1
Interphase(longest phase)
• Cells grow and prepare to divide
• Cells perform their normal function
•DNA is copied
Cell Cycle: Stage 2
Mitosis
• Cell division occurs
• DNA in nucleus is divided into
Cell Cycle: Stage 3
Cytokinesis
• Cytoplasm, organelles, and cell membrane divided to form 2 identical cells
• Final part of cell division
• Two identical daughter cells are produced
Mitosis
• 4 stages of the replication of the molecules
• PMAT
Prophase
• the first stage of Mitosis
• the chromosomes condense and become visible
• the centrioles form and move toward opposite ends of the cell (“the poles”)
• the nuclear membrane dissolves
• spindle fiber from each centriole attach to each sister chromatid
Metaphase
• second stage of Mitosis
• the centrioles complete their migration to the poles
• the chromosomes line up in the middle of the cell (“the equator”)
Anaphase
• third stage of Mitosis
• spindles attached to chromatids and begin to shorten
• this exerts a force on the sister chromatids that pull them apart
• spindle fivers continue to shorten, pulling chromatids to opposite poles
• this ensures that each daughter cell gets identical sets of chromosomes
Telophase
• fourth stage of Mitosis
• the chromosomes decondenses (stretch out)
• the nuclear membrane reform
• cytokinesis reaches completion, creating two daughter cells
• in animal cells the cell membrane pinched creating two new cells
• in plant cells a new cell wall is built between the two cells
What controls when a cell starts and stops dividing?
The nucleus instructs the cell whether to divide or not. To help make these decisions the nucleus collects messages from the cells surrounding in the form of chemical signals or “checkpoints”
The nuclear keeps the cell in interphase if:
• signals from surrounding cells tell the cell to not divide;
• signals from the surroundings let the cell know there are not enough nutrients to provide for the growth of new cells;
• the DNA within the nucleus itself has not yet been replicated;
• the DNA within the nucleus is damaged
What happens when a mutation does occur?
The cell does not divide
The 2 types of tumors: Benign tumor
• cell division is unchecked and proceeds at a moderate rate
• does not invade surrounding cells, but may physically crowd nearby cells and tissue
• does not spread to other parts of the body
• relatively harmless unless found in a part of the body, such as the brain, where it may press on (crowd out) other cells
• Benign tumors are referred to as non-cancerous
The 2 types of tumors: Malignant tumors
• cell division is unchecked and occurs very quickly. Cells spend little time in interphase
• damages and destroys surrounding tissue
• can undergo metastasis, in which cancer cells break away from the original (primary) tumor and move to a different part of the body and start a new (secondary) tumor
• may interfere with the function of the other cells, sometimes resulting in death if the tumor is not destroyed or removed
• a part of the tumor can be removed surgically and put through tests to determine if the tumor is benign or malignant this is called a biopsy
How do these cancers actually become fatal?
Cancer will eventually take over enough of the cells in the location to greatly affect what that body part is meant to do.
Specialized Cells
We have many different types of cells. Each has its own function. They have physical and chemical differences that are suited to their functions. I.e. Muscle cells use a lot of energy, therefore they contain many mitochondria.
Red Blood Cell Structure
• have a depression to increase surface area to carry more oxygen
• contains the oxygen-transporting pigment, hemoglobin
• do not have a nucleus (or mitochondria or any other organelles)
Red Blood Cell Function
• function take-up, transport, and release of oxygen to the tissues
• small amount of CO2 transport. Lack of organelles crates more space for oxygen transport.
Leukocytes (White Blood Cells) Structure
• highly mobile and capable of amoeboid movements (using cytoplasm to “crawl” along surfaces)
• Phagocytic- engulfs foreign or dead cells
Leukocyte Function
• seeks out and destroys microbes inside body (fight off disease and infection)
• able to squeeze through tight spaces to reach the site of infection (fewer of these than red blood cells, much larger than red blood cells)
Platelet Cells
• cause blood clotting
• fewer than white blood cells, smallest blood cells
Human Muscle Cells Structure
• muscle cells are long and thin, which allows them to change size easliy
Muscle Cells Structure
• cylindrical shape with banded myogibrils
• capable of contraction (shortening)
Muscle Cells Function
• move voluntary muscles acting on skeleton
Sperm Cell Structure
• motile (moved spontaneously), flagellated (has a tail like structure) cell with mitochondria
• nucleus forms a large proportion of the cell
Sperm and Egg Cell Function
• male gamete for sexual reproduction (sperm)
• female gamete for sexual reproduction (egg)
• mitochondria in sperm provide the energy for motility
Human Nerve Cells
• nerve cells have long extensions that carry messages a long distance
• carry these messages using electrical impulses
Human Fat (adipose) Cells Structure
• spherical cell with a large fat-filled vacuole
• nucleus pushed to the cell edge
Human Fat (adipose) Cells Function
• fat storage- cell fill entirely with fat
Human Skin Cells
• first line of defense for your body against “invaders”
• overlap to make it difficult for foreign objects to enter the body
Systems- Levels of Organization
• all organisms and their structure and function can be broken down into different levels of organization
• these levels begin at the simplest point, then become more complex as we move through the system of organization
Levels of Organization- Level 1- Cells
• are the basic unit of structure and function in living things
• may serve a specific function within the organism
• examples- blood cells, nerve cells, bone cells, etc
Levels of Organization- Level 2- Tissues
• made up of cells that are similar in structure and function which work together to perform a specific activity
• examples- blood, nervous tissue, bone tissue, etc
• humans have 4 basic tissues:
A. Muscle (skeletal, smooth, cardiac)
B. Connective
C. Epithelial
D. Nervous
Smooth Tissue “ Involuntary Muscle”
• found within walls of organs and structures such as the esophagus, stomach, intestines
• not under voluntary control
Cardiac Muscle
• also an “involuntary muscle” but is more like the structure of skeletal muscle, and is found only in the heart
Skeletal Muscle “Voluntary Muscle”
• attached to bones by tendons
• used to give and maintain posture in an organism
• used to allow movement of organism such as locomotion
• an average adult male is made up of 42% of skeletal muscle and an average adult female is made up of 36% (as a percentage of body mass)
Connective Tissue
• we are mostly connective tissue
• thin membranes of connective tissue (also called fascia) surround every muscle, bone and nerve in the body
• the human body runs on its connective tissue infrastructure
Epithelial Tissue
• acts as an interface between the body and the rest of the world
• your skin is composed to epithelial tissue, and epithelial tissue also lines your body cavities and major organs. The tissue is different depending on the function
• this tissue, known collectively as the epithelium
• can filter, absorb, and diffuse various substances
• also involved in sensory perception and bodily secretions
Nervous tissue
• nervous tissue is the main component of the nervous system
• nervous system- regulates and controls body functions, every time you get pinched, part of your nerve tissue is damaged
Levels of Organization- Level 3- Organs
• made up of tissues that work together to perform a specific activity
• organs include the brain, the lungs, the liver, the stomach, the arteries, and the muscles
• your senses are also organs- ears, tongue, eyes, nose, and skin are called: sensory organs
Levels of Organization- Level 4- Organ Systems
• groups of two or more organs that work together to perform a specific function for the organism
Circulatory System
Heart, blood, and blood vessels
Digestive System
Salivary glands, esophagus, stomach, liver, pancreas, intestines, rectum, and anus
Endocrine System
Hypothalamus, pituitary gland, thyroid, and adrenals
Integumentary System
Skin, hair, and nails
Lymphatic System
Organs, ducts, and nodes
It transports a watery clear fluid called lymph. Defends against diseases
Muscular System
Muscles
Nervous System
Nerves, brain, spinal cord, and peripheral nerves
Reproductive System
Ovaries, fallopian tubes, uterus, mammary glands, testes, vas deferents, seminal vesicles, and prostate
Respiratory System
Pharynx, larynx, trachea, bronchi, lungs, and diaphragm
Skeletal System
Bones, cartilage, ligaments, and tendons
Urinary System
Kidneys, ureters, bladder, and urethra
Levels of Organization- Level 5- Organisms
• entire living things that can carry out all basic life processes
• meaning they can; take in materials, release energy from food, release wastes, grow, respond to the environment, and reproduce
• usually made up of organ systems, but an organism may be made up of only one cell such as bacteria or protist
• examples- bacteria, amoeba, mushroom, sunflower, human
What is the Digestive System?
• the digestive system is a long, muscular tube
• the entire system is approximately 9m in length and is usually a one way tract
Why do we need the Digestive System?
• our body cannot readily use food
• some foods are too large and not water soluble
• the digestive system breaks down the food we eat into small pieces that can be metabolized (used for energy) by individual cells in our body
• we must eat foods that contain nutrients (carbohydrates, lipids, proteins, vitamins, minerals, water) so our body can function and provide us with the energy we need
Step 1 of Digestion- Ingestion
• the taking in of nutrients
Step 2 of Digestion- Digestion
• mechanical breakdown of food
• chemical breakdown of food
Step 3 of Digestion- Absorption
• the taking up of digested molecules into the cells of the digestive tract where they enter our bloodstream on their way to each of our body’s cells
Step 4 of Digestion- Elimination
• waste products of the digestive process are eliminated from the body
Mouth
• the first part of digestive system
• where food enters the body
• chewing and salivary enzymes in the mouth are the beginning of the digestive process (breaking down the food)
Esophagus
• the long tube between the mouth and the stomach
• it uses rhythmic muscle movements (called peristalsis) to force food from the throat into the stomach
Stomach
• a sack-like, muscular organ that is attached to the esophagus
• when food enters the stomach, it is churned in an acid bath
Small intestine
• Duodenum- the first part of the small intestine; it is C-shaped and runs from the stomach to the jejunum
• Jejunum- the long, coiled mid-section of the small intestine; it is between the duodenum and the ileum
• Ileum- the last part of the small intestine before the large intestine begins
Large Intestine
• Cecum- the first part of the large intestine; the appendix is connected to the cecum
• Ascending Colon- the part of the large intestine that runs upwards; it is located after the cecum
• Transverse- the part of the large intestine that runs horizontally across the abdomen
• Descending Colon- the part of the large intestine that run downwards after the transverse colon and before the sigmoid colon
• Sigmoid Colon- the part of the large intestine between the descending colon and the rectum
Rectum
• the lower part of the large intestine, where feces are stored before they are excreted
Anus
• the opening at the end of the digestive system from which feces (waste) exits the body
Gall Bladder
• a small, sac-like organ located by the duodenum. It stores and releases bile (a digestive chemical which is produced in the liver) into the small intestine
Liver
• a large organ located above and in front of the stomach. It filters toxins from the blood, and makes bile (which breaks down fats) and some blood proteins
Pancreas
• an enzyme-producing gland located below the stomach and above the intestines. Enzymes from the pancreas help in the digestion of carbohydrates, fats and proteins in the small intestine
Appendix
• a small sac located on the cecum
Circulatory System
• blood, heart and blood vessels
• purpose- delivers oxygen and nutrients to all parts of the body, carries wastes (ex.carbon dioxide) from tissue for disposal
Superior Vena Cava
• on if the two main veins bringing de-oxygenated blood from the body to the heart
• veins from the head and upper body feed into the superior vena cava, which empties into the right atrium of the heart
Inferior Vena Cava
• one of the two main veins bringing de-oxygenated blood from the body to the heart
• veins from the legs and lower torso feed into the inferior veins cava which empties into the right atrium of the heart
Right Atrium
• receives de-oxygenated blood from the body through the superior vena cava and inferior vena cava
Atrioventricular Valve (AV Valve)
• separates the atriums from the ventricles
• all of the valves open to allow the blood through then quickly shut to keep the blood from going in the opposite (wrong) direction
Right Ventricle
• receives de-oxygenated blood as the right atrium contracts
• contracts to pump the blood into the pulmonary artery toward the lungs
Pulmonary Valve
• separates the right ventricle from the pulmonary artery
Pulmonary Artery
• the vessel transporting de-oxygenated blood from the right ventricle to the lungs
• a common misconception is that all arteries carry oxygen-rich blood. It is more appropriate to classify arteries as vessels carrying blood away from the heart
Pulmonary Vein
• the vessel transporting oxygen-rich blood from the lungs to the left atrium
Left Atrium
• receives oxygenated blood from the lungs through the pulmonary vein
Left Ventricle
• receives oxygenated blood as the left atrium contracts
• contracts to pump blood into the aorta and flow throughout the body
Aortic Valve
• separates the left ventricle from the aorta
• is opens to allow the oxygenated blood collected in the left ventricle to flow throughout the body
Aorta
• largest single blood vessel
• carries oxygen-rich blood from the left ventricle to the various parts of the body
Septum
• the muscular wall separating the right and left sides of the heart
Gas Exchange
• is the process where oxygen from the external environment is exchanged with carbon dioxide from the internal environment
Breathing
• a muscular action that moves oxygen across gas exchange membrane
Cellular Respiration
• the process of combining oxygen with glucose to produce energy and carbon dioxide
All Gas Exchange Systems Require:
- A moist thin membrane
- A structure that maximizes the surface area of the membrane
- A method of delivering oxygen to the membrane
Nose
• lined with mucous to trap dust and bacteria
• warms and moistens air
Nasal Passage
• cilia (tiny hairs) carries mucous (which is full of particles) away from the lungs
Epiglottis
• prevents food from entering the trachea
• esophagus collapses when empty, peristalsis
Larynx
• aka Adams apple (or voice box)
• contains glottis (opening) and vocal cords
Pharynx
• part of the digestive and respiratory systems
• epiglottis is here to prevent food from entering the trachea
• important for vocalization in humans
Trachea (windpipe)
• reinforced rings of “C” shaped cartilage
• secretes mucous and has cilia
Bronchi
• have rings too
• conduct air in and out
Bronchioles
• found in lungs
• no cartilage
• produce mucous
• have cilia to force mucous up their pipes
Lung
• made up of alveoli, bronchioles, and vessels
• held together by connnective tissues and nerves
Diaphragm
• very strong muscle
• helps us inhale and exhale
Capillary
• site of gas exchange
• on exhalation, they carry carbon dioxide to the lung
• on inhalation, they carry oxygen from away from the lung to tissues and cells
Alveoli
• looks like a bunch of grapes
• elastic tissue, with a moist membrane
• surrounded by calliper for gas exchange
• gas exchange with blood occurs here
Musculoskeletal System
• gives organisms the ability to physically move by using muscles and bones
• the muscular and skeletal system work together
Skeletal System- Function
• 206 bones from a rigid framework to which the tissues and organs are attached
• provides support and protection
- the brain is protected by the skull
- the heart is protected by the rib cage
• produces blood (bone marrow)
• stores minerals (calcium, phosphorus)
Skeletal System- Division
• Axial skeleton: skull, sternum, ribs, vertebra column
• Appendicular skeleton: upper and lower extremities, shoulder and pelvic girdle
Muscular System- Function
• controlled by the nervous system
• some muscles are controlled involuntarily (without conscious thought) ex: cardiac muscle
• more than 650 muscles in the human body
• muscles pull on joints and bones, allowing us to move
Muscular System- Movement
• interaction of muscular and skeletal system
• muscles are connected to bones by tendons
• bones are connected to each other by ligaments
Movement- Joints
• bones meet each other at a joint
Nervous System- Function
• high specialized network of neurons
- conduct and generate electrical impulses to carry information throughout the body
• neurons coordinate multiple functions in the body by carrying messages from:
- one area of the brain to another, the brain to body tissues, body tissues to the brain tissues
Neurons
• electrically excitable cells that process and transmit information
• neurons do not go through cell division
Central Nervous System
• includes the brain and spinal cord
• covered by membranes called meninges
• the brain is protected by the skull
• the spinal cord in protected by the vertebrae
Peripheral Nervous System
• neurons with long extensions to the rest of the body
