Cells Flashcards
What’s a prokaryotic cell?
A bacterial cell
What are the features of a prokaryotic cell?
Capsule-The capsule enables prokaryotic cells to attach to surfaces in its environment
Flagella-Flagella are tail-like and used for locomotion
Pili-Pili are used to exchange genetic material
Plasmids-small loops of DNA
Circular DNA-coiled up and floats freely
Cytoplasm-chemical reactions take place
Plasma membrane-controls movement of substances in and out of cell
Cell wall-supports structure of cell
What’s the DNA like in a prokaryotic cell?
Prokaryotic DNA is found as a circular molecule in the cytoplasm.
Some prokaryotes have smaller loops of DNA called plasmids
What’s a eukaryotic cell?
Plant or animal cell
What’s the features of a eukaryotic cell?
RER-
SER-
Nucleus-
Nucleolus-
Centrioles-
Microtubules-
Mitochondria-
Ribosomes-
Golgi apparatus-
Lysosome-
Cell membrane-
Describe the process of protein synthesis?
- protein synthesised in the ribosome/RER
-vesicles then store and transport proteins throughout the cell
-packaged into a vesicle by the RER
-vesicle then travels in cytoplasm to the Golgi apparatus
-protein is modified by Golgi apparatus
-protein packaged into vesicle by Golgi
-protein travels (in vesicles) to cell surface membrane where it fuses
-protein released into the outside environment
How are the sperm adapted?
Long tail (flagellum) enabling it to swim
Uses energy released by mitochondria
Contain acrosome in the head of sperm which releases digestive enzymes.
Describe the process of mitosis?
-INTERPHASE:
DNA replicated
Christie’s held together by the centromere
-PROPHASE:
Chromosomes become visible
Spindle fibres develop
Spindle fibres attach to centromere
Nuclear membrane disappears
-METAPHASE:
Spindle fibres move chromosomes to line up along the equator of the cell
Spindle fibres are attached to centromere
-ANAPHASE:
Spindle fibres contract
Centromere splits/breaks
Chromatids are pulled to opposite poles of cell
-TELOPHASE:
Spindle fibres disappear
Nuclear membrane reforms around chromosomes
Chromosomes become less visible
-CYTOKINESIS:
Cytoplasm divides into 2
Cell membrane splits
2 daughter cells result
What are the 6 stages of mitosis called?
Interphase
Prophase
Metaphase
Anaphase
Telophase
Cytokinesis
The xylem tissue…
Carries water and dissolved minerals
Carries them up the plant
The phloem tissue…
Transports sugars
Carries them down the plant
What’s the features of the xylem tissue?
Lignin (spirals, rings, pitted) - helps to support the plant
There’s no end walls between cells
Outer cells are not living
PARENCHYMA- living cells of the xylem (adjacent to it) - provides all minerals that xylem needs e.g glucose
Characteristics of the phloem tissue…
Contain sieve tubes
Have companion cells
Contain sieve plates
Contains cytoplasm
Has PARENCHYMA on outside of cell
What are vascular bundles?
Contain the phloem and xylem and sclerenchyma in the “Easter egg” shapes
Describe the process of meiosis
DNA replicates
DNA condenses
Chromosomes arrange themselves into homologous pairs
First division - homologous pairs have separated
Second division - pairs of sister chromatids are separated
4 new daughter cells are produced that are genetically different
What’s a homologous pair?
Pairs of matching chromosomes
What does totipotency mean?
The ability to produce all cell types
What does pluripotency mean?
The ability of a stem cell to produce all the specialised cells in an organism
What’s the structure and function of the cell wall?
Rigid structure used to support cell, supports plant cells
What’s the structure and function of the middle lamella?
Outermost layer of the cell, adhesive layer - can sticking adjacent plant cells to another
What’s the structure and function of the plasmodesmata?
Channels in the cell walls, allows transport of substances
What’s the structure and function of pits?
Regions of cell wall where it’s very thin and arranged in pairs, allow transport of substances between cells
What’s the structure and function of chloroplasts?
Flattened structure surrounded by a double membrane, photosynthesis takes place here
What’s the structure and function of amyloplasts?
Small organelle enclosed in a membrane, store starch grains
What’s the structure and function of vacuole and tonoplast?
Vacuole is compartment surrounded by the tonoplast (membrane), vacuole keeps cell turgid (contains water) and tonoplast controls what enters and leaves the cell
What’s the function of schlerenchyma fibres?
Provide support
What are features of schlerenchyma cells?
Made of bundles of dead cells
Hollie lumen and longer than they are wide
Have end walls
Walls contain lignin and have more cellulose
What’s the purpose / function of starch?
Energy storage material in plants
What do amylose and amylopectin (2 alpha glucose) make up?
Starch
What is amylose?
Ping unbranched chain of ã glucose
Coiled structure
Compact so good for storage
What is amylopectin?
Long unbranched of ã glucose
Branched - glucose can be released quickly
Is starch insoluble to soluble in water?
Insoluble in water
What is cellulose?
Major component in cell walls in plants
What’s the structure of cellulose?
Long unbranched chains of ß glucose
1-4 glycosidic bonds
Cellulose chains are straight because…
Glycosidic bonds are straight
50-80 cellulose chains are joined together via?
Hydrogen bonds
What do hydrogen bonds forming mean?
Microfibrils form
Where is pectin made?
In the middle lamellae
