The Plant Cell And The Cell Cyle Flashcards
Prokaryote
Eukaryote
Before a nucleus - bacteria and archaea
-lack nucleus (DNA not surrounded by membrane)
-have circular bacterial chromosome in nucleoid
-lack membrane bound organelles
-non cytoskeleton
True nucleus
-DNA linear in nucleus
-membrane bound organelles
-cytoskeleton
Protoplast
Contents of cells Consisting of a cytoplasm with membrane bound organelles and a nucleus
Plasma membrane functions
- Separates protoplast from outside
- Mediates transport in and out
- Synthesis of cell wall microfibrils (cellulose)
- Detects and responds to hormonal and environmental signals
Tonoplast
Single membrane around vacuoles
Cytoplasmic streaming or cyclosis
Movement within the cell as long as cell is alive
Nucleus functions
- Controls ongoing activities by determine which and when protein molecules are produced
- Stores genetic info (DNA) - nuclear genome
Endoplasm if reticulum
A complex system of membranes that plays a central role in cellular biosynthesis.
Chromatin and chromosomes
Threads and Grains easily distinguished
During division, chromatin become condensed until visible as distinct chromosomes
Haploid
Diploid
Polyploid
Number of chromosomes in gametes is half the somatic cell
Somatic cell (double set)
3n, 4n, 5n
Nucleoli
A small spherical body found in the nucleus of eukaryotic cells; composed chiefly of rRNA that is in the process of being transcribed from copies of rRNA genes; the site of production of ribosomal subunits
Ribosomes
Small particles, consisting of protein and RNA. Has a large and small subunit produced in nucleolus and transported to cytoplasm, where they are assembled into ribosomes. Ribosomes are where amino acid are linked together to form proteins
May aggregate into polysome areas
Plastids
Concerned with photosynthesis and storage-chloroplasts (with chlorophyll and carotenoid), chromoplasts, and leucoplasts
Plastids are differentiators into a membrane system consisting of flattened sacs called thylakoids and a matrix called the stroma
Chloroplast jobs besides photosynthesis
Involves in synthesis of amino acids, fatty acids and a number of secondary metabolites and temporary storage of starch
-contain own DNA
Chromoplasts
Pigmented plastids of variable shape, lacking chlorophyll but synthesize and retain carotenoid pigments (yellow, orange, red). Has no membranes
May develop from previous chloroplasts (ripening of fruits from green to yellow)
Leucoplasts
Lack pigments and an elaborate system of inner membranes. Some synthesize starch, other are capable of forming oils and proteins.
Lest differentiated
Contains amyloplasts
Proplastids
Small, colourless, or pale green undifferentiated plastids that occur in meristematic cells of roots and shoots. Precursors to highly differentiated plastids. In embryos, pro plastids of seeds first develop into etioplasts, and then with light become chloroplasts
Can become amyloplast, chromoplasts or mature chloroplast
Prolamellar bodies
Proplastid differentiation development is arrested due to a sense of light, a prolamellar body is formed.
Etioplasts
Plastids containing prolamellar bodies
-form in lead cells of plants grown in the dark. When exposed to light, the eptioplasts develop into chloroplasts, and membranes of prolamellar bodies develop into thylakoids
Mitochondria
Like plastids, are surrounded by 2 membranes. Inner membrane has numerous invaginations called cristae to increase surface area for proteins and reactions. Generally smaller than plastids.
Sites of respiration, a process involving the release of energy from organic molecules and it’s conversion to molecules of ATP.
What organelle plays a role in programmed cell death
Mitochondria
In plant cells, genetic information is found in which organelles
Plastids, mitochondria and nucleus
Symbiosis
Close association between two or more dissimilar organisms that may be, but is not necessarily beneficial to each
Peroxisomes
Or micro bodies
Are spherical organelles that have a single membrane.
Some photorespirate and some contain glyoxysomes
Photorespiration
A process that consumes oxygen and releases carbon dioxide