Cell Structure and Cell Division Flashcards
cell
was first used by Robert Hooke in 1665, when he examined the bark of cork tree under a compound microscope
3 major parts of a cell
- plasma/cell membrane
- the cytoplasm
- the nucleus
plasma membrane
- 45% lipid, 50% protein, 5% carbohydrate
- lipids are arranged in bilayer with peripheral proteins attached and integral proteins extending through the membrane
- envelops entire cell
- provides a barrier for cell by regulating movement of materials in & out of cell
cytoplasm
- mixture of water, salts, and organic molecules to form a thick fluid and organized structures called organelles
- region between plasma membrane and nucleus
- region of cellular metabolism and other activities that maintain the cell
cytosol
- thick, gel-like fluid composed mostly of water and proteins
- surrounds organelles
- transport substances between organelles and other cell structures
organelles
- formed bodies
- suspended within cytosol
- varied activities that maintain the cell
centrioles
- composed of nine groups of three microtubles, forming a cylinder
- near the nucleus in the centrosome
- participate in cell division
Cilia
- long, slender projections of the plasma membrane of certain cells
- extend outward, away from the cell surface
- rhythmic movements propel fluids
microvilli
- numerous, tiny folds of the plasma membrane that increase the surface area of certain cells
- extend outward away from the plasma membrane
- increase the plasma membrane surface area for absorption or secretion
ribosomes
- very, small, spherical structures composed of 60% RNA and 40% protein
- either attached to the ER or unattached in the cytoplasm
- provide attachment site for mRNA during protein synthesis
rough endoplasmic reticulum (RER)
- branching tubules that may be flattened or tubular, with attached ribosomes
- extends between nucleus and plasma membrane
- site of protein synthesis
smooth endoplasmic reticulum (SER)
- branching tubules that may be flattened or tubular, without ribosomes
- winds and twists throughout cytoplasm
- site of lipid and carbohydrate assembly
golgi apparatus (complex)
- series of flattened, disc-shaped sacs
- usually near nucleus with secretory vesicles near plasma membrane
- prepares and packages cellular products of transport
mitochondria
- spherical or sausage shaped with inner folded membrane
- randomly throughout cytoplasm
- site where nutrients are broken down and ATP is produced during cellular respiration
peroxisomes
- small, spherical
- randomly throughout cytoplasm
- site where free radicals are detoxified
lysosomes
- small, spherical
- randomly throughout cytoplasm
- contains enzymes that breakdown materials brought into the cell, or releases enzymes out of the cell to digest
nucleus
- large structure composed of a double membrane that contains nucleic acids
- often located in center of cell
- contains DNA, which regulates protein synthesis and cell division and contains RNA
nuclear envelope
- double membrane with large nuclear pores
- surrounds nucleoplasm
- regulates movement of materials between cytoplasm and nuceloplasm
nucleoplasm
- gel-like fluid consisting of water, nucleic acids, and proteins
- contained within the nuclear envelope
- site of nucleic acids (DNA & RNA)
Nucleoli
- small spheres containing RNA + proteins
- grouped in area of nucleoplasm
- site of RNA synthesis
Chromatin
- threadlike material composed of DNA and proteins
- throughout the nucleoplasm
- DNA contains genes which control protein synthesis
skeletal muscle cell shape
long and cylindrical. the shape allows it to extend long distances to connect to bones & contract
neuron cell shape
star-shaped or long and narrow with many branches
cheek cell shape
round and flat
cell cycle
a series of events which a eukaryotic cell must undergo in order to divide to produce the two daughter cells
interphase
the cells grow and get ready to divide. 2 gap phases: G1 and G2 and S (synthesis) phase where DNA replicates and get ready for cell division.
Mitotic (M) phase
- prophase
- prometaphase
- metaphase
- anaphase
- telophase
- cytokinesis & karyokinesis
cytokinesis
actual separation of the two daughter cells
karyokinesis
the nucleus divides into two daughter nuclei
G0 phase
Cells that don’t divide because of genetic programming (ex: neurons)
G1 Phase
growth and normal metabolic roles
Synthesis Phase
DNA and organelle replication
G2 Phase
growth and preparation of mitosis
somatic cell division
- when cells reach a certain size/age they divide to form identical daughter cells
- provides body growth, replacement of older cells, and repair injured parts of body
- 2 processes: mitosis & cytokinesis
Mitosis aka nuclear division
- the sequence of changes that the nucleus and its DNA undergo in preparation for cell division.
- Includes four phases: prophase, metaphase, anaphase, and telophase
Cytokinesis aka cytoplasmic division
the sequence of changes occurring in the cytoplasm and plasma membrane resulting in physical separation to form two daughter cells.
Cytokinesis aka cytoplasmic division
the sequence of changes occurring in the cytoplasm and plasma membrane resulting in physical separation to form two daughter cells.
