Wk 8 & 9 REMEMBER Flashcards
50%PROB OF BEING IN EXAM
Cell Theory:
* the cell is the basic structural and functional unit of life
* activity of the organism depends on individual and collective activity of cells
* biochemical activities of cells are dictated by us cellular structure
* continuity of life has a cellular basis
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Mitochondria = power house = energy
Why are mitochondria present in all aerobic cells?
Aerobic cells = oxygen which use/burn energy & mitochondria = power house = energy
Diffusion - oxygen & co2 eg. Diffuse between phospholipid molecules
* movement of any type of molecule (diffusion)
Osmosis - internal diffusion of water molecules (osmosis)
Plasmalemma = cell membrane
Composition: lipid bilayer containing phospholipids, steroids, proteins, and carbs
Function: isolation, protection, sensitivity, support, control of entrance/exit of materials
Cytosol
Composition: fluid component of cytoplasm, may contain inclusions of insoluble materials
Function: distributes materials by diffusion, stores glycogen, pigments and other materials
Functions of plasmalemma -
* cell membrane (aka phospholipid bilayer)
Major functions:
- controls permeability of cell (environment)
- structural support
- sensitivity to particular messenger molecules
Membrane permeability of plasmalemma: Passive processes - * diffusion * osmosis * facilitative diffusion
Active processes-
- endocytosis (takes something inside)
- cell eating, cell drinking, receptor-mediated endocytosis
Plasma membrane surfaces
- 20% of all membrane lipid is cholesterol
Membrane flow: BE AWARE
- this is the continuous movement and recycling of the cell membrane
REALLY IMPORTANT Cell life cycle: Prophase Metaphase Anaphase Telophase Cytokinesis
Cell division = division of genetic material in the cell
- essential for body growth and tissue repair
- mitosis - nuclear division
- cytokinesis - division of the cytoplasm
P.P.M.A.T ******NEED TO KNOW**** Prophase: - chromosomes condense and become visible - mitotic spindle starts to form Prometaphase: - nuclear envelope dissolves - spindle fibers attach to kinetochores Metaphase: - chromosomes line up at the equator of the cell Anaphase - chromatids are pulled apart Telophase: - new nuclear envelopes form - cell begins to pinch in two (cytokinesis) Cytokenisis:?
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Control of cell division = out of control equals cancer
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Organelles - description of both form and function
* THE NUCLEOLUS: form-dense spherical (non-membrane-bound) bodies, composed of ribosomal RNA and proteins. function-site of ribosome subunit manufacture.
* THE NUCLEUS: form-largest organelle. Surrounded by the nuclear envelope; contains fluid nucleoplasm, nucleoli, and chromatin. Function-control centre of the cell; responsible for transmitting genetic info and providing the instructions for protein synthesis.
* THE NUCLEAR ENVELOPE: form-double membrane pierced by pores. Outer membrane continuous with the endoplasmic reticulum function-separates the nucleoplasm from the cytoplasm and regulates passage of substances to and from the nucleus.
* CENTRIOLES: form-paired cylindrical bodies each composed of 9 triplets of microtubules function-organise a microtubule network during mitosis (cell division) to form the spindle and asters. Form the bases of cilia and flagella.
* MICROTUBULES: form-cylindrical structures made of tubulin proteins function-support the cell and give it shape. Involved in intracellular and cellular movements. From centrioles and cilia and flagella, if present.
CONT…
- GOLGI APPARATUS: form-stack of flattened membranes and associated vesicles close to the nucleus. Function-packages, modifies and segregates proteins for secretion from the cell, inclusion in lysosomes and incorporation into the plasma membrane.
- MITOCHONDRION: form-rodlike, double-membrane structures; inner membrane folded into projections called cristae. Function-site of ATP synthesis; powerhouse of the cell
- PLASMA MEMBRANE: form-membrane made up of a double layer of lipids within which proteins are embedded. Proteins may extend entirely through the lipid bilayer or protrude on only one face. Most externally facing protein and some lipids have attached sugar groups. Function-external cell barrier. Acts in transport of substances into or out of the cell. Maintains a resting potential that is essential for functioning of excitable cells. Externally facing proteins act as receptors (for hormones, neurotransmitters, and so on), transport proteins and in cell-to-cell recognition.
Detailed diagram of plasmalemma or cell membrane (see photos)
- wave like shape (remember)
- double bilayer of lipids with embedded, dispersed proteins
- bilayer consists of phospholipids, cholesterol and glycolipids
* glycolipids are lipids with bound carbohydrate
* phospholipids have hydrophobic and hydrophilic bipoles
My notes say - mainly lipids, floats - oil slick on ocean - double layer barrier between extracellular fluid and intracellular fluid (Fluid Mosaic Model)
Structure and appearance (Matching pairs)
- Cytoplasm - jellylike matrix
- Mitochondria - membranous sacs; folded internally
- lysosomes - membranous sacs
- endoplasmic reticulum - interconnected tubules and sheets
- Golgi apparatus - flattened, membranous sacs
- chromatin - protein and DNA molecules
- cilia - cytoplasmic extensions
- cell membrane - phospholipid and protein
- centrosomes - rodlike centrioles
- ribosomes - granular particles
Structure and Function (matching pairs)
- cytoplasm - suspended organelles
- mitochondria - transform energy into ATP
- lysosomes - digest molecules and worn cells
- endoplasmic reticulum - cellular framework and transport
- Golgi apparatus - synthesise carbohydrates; secrete lipids and glycoproteins
- chromatin - controls cellular activity
- cilia - movements at cells surface
- cell membrane - selectively permeable
- centrosome - distribute chromosomes during mitosis
- ribosomes - synthesise proteins
