Cells Make up the Human Body [2] Flashcards
Name the 6 main structures in a cell and their functions
Cell membrane: the outer boundary of the cell.
Cytoplasm: parts of the cell within the membrane, except for the nucleus.
Organelles: structures suspended in the cytoplasm that carry out specific functions.
Cytosol: liquid part of cytoplasm, 75-90% water.
Cytoskeleton: scaffolding of protein fibres, provides cell structure.
Inclusions: chemical substances in the cytoplasm, e.g. haemoglobin and pigments.
State the structure, location and function of the nucleus.
A spherical organelle protected by a double nuclear membrane. Stores DNA, which contains inherited information and controls the cell’s function.
State the structure, location and function of the ribosome.
Very small spherical organelles that join amino acids to form proteins. Found free in the cytoplasm or at the endoplasmic reticulum.
State the structure, location and function of the endoplasmic reticulum.
Pairs of parallel, labyritnth-like membranes surrounding the nucleus. Transports molecules and provides a surface for chemical reactions.
State the structure, location and function of the golgi body.
Stacked membranes near the nucleus that package proteins (produced by ribosomes and transported via ER) into vesicles for excretion.
State the structure, location and function of lysosomes.
Small membrane-bound spheres formed by the golgi body containing digestive enzymes. Break down large molecules or material inside incoming vesicles.
State the structure, location and function of the mitochondria.
Sausage-like organelles spread throughout the cytoplasm with a double membrane. Inner membrane provides surface area for cellular respiration to occur.
State the structure, location and function of cillia and flagella.
Projections from the cell that assist in movement of the cell or its inner contents. Cilia: hairy, flagella: tail.
Describe the structure of the cytoskeleton and its function.
Framework of microtubules and microfilaments that gives cell structure and assists in movement.
Microtubules: hollow rods controlling organelle movement
Microfilaments: move organelles or entire cell
Name examples of inclusions
Haemoglobin, pigments in eyes/hair, melanin.
What is the centriole
Organelle in animal cells that form spindle fibres during cell replication
What is the difference between rough and smooth endoplasmic reticulum
Rough ER: lined with ribosomes, transports proteins
Smooth ER: manufactures lipids
What is extracellular fluid and its function
The immediate environment outside of cell membrane, transports materials travelling to or from cells.
What is homeostasis
Where body systems cooperate to maintain a constant cellular environment (fluid must have constant temperature and concentration)
Describe the structure of the cell membrane
Fluid mosaic model - many kinds of molecules constantly changing position
Phospholipid bilayer - each phospholipid has a hydrophillic phosphate head and a hydrophobic lipid tail
Semi-permeable - allow certain molecules through more easily than others
Proteins (receptor, carrier, channel, cell identity marker, cholesterol)
What are the functions of the cell membrane
- physical barrier between cytoplasm and fluid as their compositions are different
- regulates passage of materials (intake of ions and nutrients, removal of waste)
- senses changes in extracellular fluid
- supports cell
What is simple diffusion
The spreading out of liquid and gas molecules along the concentration gradient (from areas of high to low concentration).
What is osmosis, and what is the most important solvent in the human body
The diffusion of a solvent through a semi-permeable membrane along the concentration gradient (passive process). Water is the most important solvent.
What are the three types of cells influenced by osmosis?
Hypotonic - higher concentration of water inside of cell than out (bulging/swelling)
Isotonic - equal concentration of water on both sides (normal)
Hypertonic - lower concentration of water outside of cell than inside (dehydrated and shrivelled)
What is facilitated transport, and what are the two types of proteins?
Where proteins in the cell membrane allow molecules to pass through.
- Channel proteins: allow dissolved molecules to pass through, avoiding hydrophobic inner portion.
- Carrier proteins: changes shape so that it opens on one side at a time.
What are the characteristics of carrier mediated transport
Molecule - specific
Carriers can become saturated (will not go faster if concentration increases)
Hormones regulates carrier mediated transport
What is carrier mediated transport, and what are the two types
Proteins that open on one side at a time allow molecules through.
Facilitated diffusion and active transport
What is active transport
What is an example of active transport
An active process that moves substances against the concentration gradient through carrier proteins
Example: sodium pump
What is facilitated diffusion and examples of molecules that use this process
When substances are transported across the membrane along the concentration gradient through carrier or channel proteins
Examples: glucose and amino acids
What is vesicular transport?
Movement of substances across the membrane in vesicles (active process)
What is endocytosis, phagocytosis and pinocytosis
Where the membrane folds around a particle to form a vesicle and pinches off, suspended in the cytoplasm.
Phagocytosis: solids
Pinocytosis: liquids
What is exocytosis?
Where a vesicle inside the cell fuses with the cell membrane, and its contents are excreted
Why are cells so small?
A large cell would have a smaller Surface Area to Volume ratio, and is unable to transport nutrients throughout the cell efficiently.
What is a tissue and its four types
A group of cells that work together to carry out a particular task
Epithelial, connective, muscular, nervous
What is epithelial tissue, its function, its appearance, and its location
Covering or lining tissue that lines inner surface of tubular organs.
Cells are packed closely to form smooth surfaces.
Vary in shape - cube or column shaped, flat and thin
Found in heart, stomach, intestines, mouth and other hollow organs. Outer layer of skin is epithelial.
What is nervous tissue, its function, its appearance, and its location
Made up of neurons that use electrical impulses and chemicals to pass messages around the body
Found in brain, spinal cord, nerves
What is connective tissue, its function, its appearance, examples, and its location
Supporting tissues that holds/connects body parts together.
Characteristics: cell are not closely packed like epithelium, separated by a matrix (non cellular material)
Examples: bone, cartilage, tendons, ligaments, adipose tissues. Blood is also classified as a connective tissue (matrix is the liquid between blood cells)
What is muscular tissue, its function, and its three types
Aka muscle fibres, long, thin tissues that can contract for movement. They are elastic, contractible, extensible and exciteable. Three types are skeletal, smooth and cardiac
Describe the characteristics of skeletal muscle (function, appearance, location)
Form of muscular tissue that are attached to bones
Voluntary (can control)
Striated (have stripes across them)
Describe the characteristics of smooth muscle (function, appearance, location)
Form of muscular tissue found in organs such as intestines, stomach, iris, uterus, walls of blood vessels.
They contract involuntarily to carry out unconscious processes such as digestion.
Non striated.
Describe the characteristics of cardiac muscle (function, appearance, location)
Form of muscular tissue that makes up most of the heart, involuntarily contracts to pump blood throughout the body.
Striated.
Which muscle tissues are striated?
Cardiac and skeletal
