A.2.2 CELL STRUCTURE Flashcards
Outline the components of cell theory.
- All living things are made of cells
- Cells are the basic unit of life
- Cells arise from other cells
Describe the difference between multicellular and unicellular organisms.
MULTICELLULAR:
1. Made of many cells
2. have specialised cells to carry out particular functions
3. functions of life carried out in part/whole by cells in plants, animals, and some protists dpending on the functions of specialised cells
UNICELLULAR:
1. made of one cell
2. Have specific functions of life that organisms must perform in order to be alive
3. prokayrotes/bacteria, yeast, algae, and some protists have to peform all of the functions in one cell
Ex of unicellular:
1. Amoeba: a protozoan of fresh water habitats
2. Escherichia coli: bacterium found in intestines of animals/humans
3. Chlamydomonas: a motile alga of fresh water habitats, rich in ammunium ions
What are the processes of life that organisms must undergo to be considered alive?
Unicellular organisms like paramecium undergo ME HNGRI: ME H(u)NGRI
Metabolism
Excretion
Homeostasis
Nutrition
Growth
Reproduction
Irritability
Metabolism: web of enzyme controlled chemical reactions in a cell/organsims
Excretion: removal of metabolic waste like co2, urea, water
Homeostasis: maintaining constant internal conditions like pH, water, temp
Nutrition: the process of an organsims obtaining matter/energy from its environment
Growth: multicellular organsims increase by cell divison/mitosis, whereas unicellular organisms grow by increasing in size, cytoplasm, and # of organelles
Reproduction: produces offspring either sexually (meisosis/fertilisation) for multicellular organsims or asexually (mitosis) for unicellular organsims, or binary fission for bacteria
Irritability: living things response to and react with environment like temperature, light, or chemicals
Explain how cells arise from other cells.
All cells multiply by cell division, and all live evolved fro simpler ancestors. Louis Pasteur refuted the idea of spontaneous generation with his experiments.
MITOSIS (& cytokinesis):
1. produces 2 identical daughter cells
2. occurs in all body cells
3. allows for growth in multicellular organisms/asexual production in unicellular organisms
MEIOSIS (&cytokinesis)
1. produces 4 unique daughter cells with 1/2 DNA
2. Results in sex cells (egg and sperm)
3. Allows for sexual reproduction in multicellular organsims
BINARY FISSION:
1. allows for reproduction in prokayrotes/bacteria cells
Draw, label, and describe the functions of the prokaryotic cell.
Diagram should include:
1. cell wall: provides support, strength, and shape. Prevents bacteria from bursting in hypotonic conditions. Made of peptidolygcan (amino sugars + polypeptides)
2. plasma membrane: controls what enters and exists)
3. free floating ribosomes (70s): protein synthesis
4. flagellum: moves bacteria
5. nucleoid (single circular chromosne): genetic material, much smaller than eukayrotic genomes
6. Pili : attachment of the bacteria to surfaces like teeth
7. Plasmid: small circular DNA that allows for antiboitc resistance
8. Capsule
- Bacillus/rod shape
- Length 2x the width
- rounded corners
- approximate width of 0.5 um, length of 2.0 um
Outline the structure and function of the nucleus within eukaryotic cells.
STRUCTURE:
1. Double membrane
2. Pores/holes: allows for movement of mRNA
3. Contains genetic info in the form of chromosomes (DNA & associate histone proteins) and Chromatin (uncoiled chromosones that stain dark, and concentrated at edge of nucleus)
FUNCTION: Contains hereditary/genetic information
Describe the structure and function of mitochondrion within eukayrotic cells.
STRUCUTRE:
1. Double membrane
2. Smooth outer membrane and folded inner membrane
3. Folds are referred to as cristae
4. Variable in shape
FUNCTION: site of energy/ATP reproduction by aerobic respiration
Describe the structures and functions in eukayrotic cells.
PRESENT IN ALL EUKARYOTIC CELLS:
1. Plasma membrane: regulates the movement of molecules in/out of the cell
2. Free-floating ribosomes (80s): protein synthesis
3. Nucleus: contains hereditary info/DNA with chromatin, nuclear membrane, and nuclear pore
4. Mitochondrion: site of ATP production/aerobic cellular respiration
5. Rough endoplasmic reticulum: protein synthesis designated for transport/export out of the cell
6. Golgi apparatus: processes, modifies, and sorts proteins for export
PRESENT ONLY IN ANIMAL CELLS (NOT PLANTS/PROKARYOTIC)
1. Sectory vesicles/zymogen granules (small temporary vesicles: contain digestive enzymes for export out of the cell
2. Lysome: vescile with enzymes for digestion/apoptosis
3. Centriole: not visible, but aids in microtubule structure development/ flagella synthesis
Label the structure and function of the palisade mesophyll cell of the leaf
PRESENT IN EUKAYROITC CELLS:
1. Plasma membrane
2. Free-floating ribosomes
3. Nucleus
4. Mitochondrion
5. Rough endoplasmic reticulum
6. Golgi apparatus
ONLY PRESENT IN PLANT CELLS (NOT ANIMALS)
1. Cell wall: structure and support
2. Chloroplast: produces carbohydrates through photosynthesis
3. large central vacuole: storage of water, ions and waste
4. Amyloplast: storage of carbohydrates
Recall the structures common to cells in all living organsims, and the structures common to all eukayrotic cells
ALL LIVING:
1. cytoplasm
2. ribosomes
3. plasma mebrane
4. nucleic acid/DNA
EUKAYROTIC CELLS:
1. nucleus with chromosones/DNA
2. cytoplasm
3. ribosomes
4. plasma membrane
5. mitochondria
6. golgi apparatus
7. smooth endoplasmic reticulum
8. rough endoplasmic reticulum
9. vesciles - small vs large
Compare the differences and similarities in eukayrotic cell strucutre between animals, fungi, and plants
ANIMALS:
1. centrioles present
2. lysosomes present
3. small temporary vacuoles
4. no chloroplast
5. no cell wall
6. multicellular
7. cilia and flagella can be present
PLANT:
1. no centrioles
2. no llysosomes
3. large permanent central vacuole
4. chloroplast present
5. cell wall present – made of cellulose
6. multicellular
7. no clilia/flagellated sperm
FUNGAL CELLS:
1. centrioles typically absent
2. no lysosomes
3. large vacuole present
4. no chloroplast
5. cell wall present – made of chitin
6. unicellular OR multicellular
7. no ciliar/flagella
Compare how unicellular organisms and multicellular organisms perform the functions of life
ME HNGRI
Unicellular: Prokayrotes/bacteria, yeast, algae and some protists – have to perform all of these functions in one cell
Multicellular: Plants, animals, some protists – Functions of life are carried out in part OR whole by cells; depends upon the functions of specialized cells ; functions of life are carried out in entirety by whole organsim
Apply the functions of life to the unicellular organism, paramecium
MEHUNGRI
Metabolism: CYTOPLASM AND MITOCHONDRIA - chemical reactions and the conversion of organic molecules using enzymes
Excretion: ANAL PORE – metabolic waste products (nitrogenous compounds) removed through exocytosis. Food vacuole fuses with the membrane.
Homeostasis: CONTRACTILE VACUOLE - regulates water/osmotic levels. Maintains internal environment through diffusion of o2/co2 across plasma membrane
Nutrition: ORAL GROOVE & FOOD VACUOLE - food obtained through oral groove, incorporated in food vacuole to be digested and absorbed into the cell to use.
Growth: CYTOPLASM - increases in cell size, # of organelles until it divides/reproduces
Reproduction: Asexual reproduction through BINARY FISSION - production of offspring/cells from original organism
Response: CILIA - propels organism/ cell in response to environment or stimuli (light, chemical, predators, food) by movement
Apply the functions of life to the unicellular organism, chlorella
Metabolism: CYTOPLASM & MITOCHONDRIA - chemical reactions and the conversion of organic molecules using ENZYMES
Excretion: Metabolic waste products (excess nitrogenous compounds/ o2) removed through DIFFUSION across PLASMA MEMBRANE
Homeostasis: Maintains internal environment through DIFFUSION across PLASMA MEMBRANE; stores excess GLUCOSE AS STARCH to maintain osmotic balance/water balance in STARCH CRANULES around PYRENOID
Nutrition: CHLOROPLAST produces sugars using light, co2, and h2o through photosynthesis
Growth: Increase in cell size, cytoplasm # of organelles until it divides/reproduces
Reproduction: Asexual reproduction through CELL DIVISON to create several cells (AUTOSPORES) that are released upon the disintegration of the parent cell all
Response: responds to the environment fact of light – the absence of light usually triggers nuclear, and then cell division
What characteristics of cells/organisms make them atypical samples of cells?
- Striated muscle cells
- challenges the idea that cells are small with one nuclear per cell
- muscle cells called fibres can be very long (300mm)
- each cell has more than one nucleus per cell
- each cell is surrounded by a single plasma membrane, and is multi-nucleated - Phloem/ sieve tube cells
- no nucleus
- reduced organelles
- connected with gaps - plasmodesmata/pores in sieve tube plates - Red blood cells
- lack nucleus at maturity - Giant algae
- unicellular, but very large in size (5-100mm)
- complex with 3 anatomical parts (bottom rhizoid, stalk, top umbrella branches that may be fused into a cap)
- single nucleus in the rhizoid - Asephate fungal hyphae
- very large, multinucleated
-continuous cytoplasm along the hyphae
- cell walls made of chitin
- tubular hyphae (extensions) form a dense network called a mycelium
