Ch 3 & 4 Flashcards
Phospholipid bilayer
fatty acids are away from the water and phosphate groups are in contact with the water; hydrophilic heads and hydrophobic tails; very thin solution
Intrinsic proteins
proteins partially immersed in the lipid bilayer; differ in size, shape and location of hydrophobic, lipid soluable regions
Extrinsic Proteins
AKA peripheral proteins that are located outside the membrane
Hydrophilic Domains
loves water; can mix, dissolve in and interact with water; associate mostly with phospholipid phosphates and water
Hydrophobic Domains
hates water; does not mix with or repels water; associates mostly with fatty acids and allows proteins to sink
Fluid Mosaic Membrane
a heterogeneous liquid (at least some proteins are bound to their neighbors and differentiation in diffusion takes place); many types of lipids and intrinsic proteins can diffuse laterally
Glycoproteins
a protein with sugar attached (short chains less than ten sugars long)
Vesicles (lumen)
Vesicle: small space enclosed by a membrane
Lumen: interior of a vesicle
Exocytosis
when the contents of a vesicle or vacuole are carried to the outside of the cell by fusion of the plasma membrane and the membrane of the vesicle or vacuole
Endocytosis
when material is absorbed into a cell by invagination in the plasma membrane, then it pinches and shits to form a vesicle
Selectively Permeable
some substances cross the membrane more easily and rapidly than others
Facilitated Diffusion
when large intrinsic proteins across the membrane assist in the movement of charged substances and act as hydrophillic channels
Active Transport
when molecular pumps (proteins) bind to a molecule on one side of the membrane and using energy changes shape to release the molecule on the other side
Protoplasm
all the substance of a cell not including the cell wall (single cell=protoplast); mass of proteins, lipids, nucleic acids and water
Plasma membrane
the membrane that covers the surface of the protoplasm; used for protection: impermeable to harmful substances and permeable to beneficial ones
Nucleus
stores the organism’s genetic information; contains DNA, involved in inheritance, metabolism control and ribosome synthesis
Nucleoplasm
located in the nucleus DNA; substance of a cell nucleus: histones, RNA, enzymes, nucleic acids, water
Nuclear envelope
surrounds the nucleus and composed of an outer membrane and an inner membrane; separates nuclear material from the rest of the cell
Pores
Numerous small holes in the nuclear envelope that are involved in the transport of material between the nucleus and the rest of the protoplasm
Nucleolus
Organelles in the nucleus where ribosomal RNAs are synthesized and assembled into ribosomal subunits
Central Vacuole
membrane bounded space larger than a vesicle that stores material (mostly water and salts) but sometimes contain visible crystals, starch, proteins bodies, etc
Cytoplasm
consists of nucleus, vacuoles and cytoplasm
Mitochondria
eukaryotic organelles that carry out cell respiration
Plastids
organelles only in plant cells
Chloroplasts
chlorophyll-rich plastids that carry out photosynthesis
Amyloplasts
plastids that store starch
Chromoplasts
plastids that contain red or yellow pigments located in flowers and fruits
Leucoplasts
colorless plastids; can be involved in various types of synthesis
Endoplasmic Reticulum
narrow tubes and sheets of membrane that form a network throughout the cytoplasm
Rough Endoplasmic Reticulum
ribosomes attached to the ER; involved in protein synthesis
Smooth Endoplasmic Reticulum
no ribosomes; involved in lipid synthesis
Dicytosomes
stack of thin vesicles held together in a flat or curved formation
Microbodies
vesicle-like organelles that isolate reactions that either produce or use the dangerous compound peroxide, H2O2 called photorespiration
Peroxisomes
detoxification of harmful products of photosynthesis and are closely associated with chloroplasts
Glyoxysomes
involved in respiring stored fatty acids into sugars
Microtubules
act as a cytoskeleton which holds regions of the cell surface while another part expands which allows for cell growth and expansion; assemble into arrays which catch vesicles and bring them to specific sites or cover a region to exclude the vesicles; also involved in motility
Microfilaments
composed of actin; used for structure and in the movement of organelles other than flagella, cilia or chromosomes
Cell wall
provides strength and protection to the protoplasm; structure
Primary cell wall
thin wall on all plant cells except some sperm cells; formed during cell division
Secondary cell wall
in some plant cells; formed after cell division; located interior to the primary wall and typically impregnated with lignin
Genome
entire complex of genes
Chromosome
thousands of genes in a linear sequence
Histones
special class of proteins complexed with DNA that provides structure and protection
Centromere
chromosomes that have a structural feature and located near the center of the chromosome
Telomere
caps the end of the chromosome
Gene Amplification
repeated synthesis of the DNA of one or a few genes, not the entire genome; amplified genes are those needed for the specialized metabolism of the mature cell
G1 phase
first stage after division and before synthesis of DNA in the nucleus; part of interphase; often the longest phase when the nucleus actively directs cytoplasmic metabolism; synthesis of nucleotides used for the DNA replication
S Phase
DNA replication; the genes in the nucleus are replicated
Endoreduplication
repeated synthesis (replication) of nuclear DNA in the absence of cell division
G2
part of interphase between the synthesis of DNA and the beginning of nuclear division; cells prepare for division
Mitosis
duplication division
Prophase
first phase of mitosis: the nucleus and nuclear membrane break down, the chromosomes condense and the spindle forms
Metaphase
second phase of mitosis: the chromosomes move to the center of the spindle, the metaphase plate
Anaphase
the third phase of mitosis: centromeres divide and two chromatids of the chromosome become independent chromosomes; the two are pulled to opposite poles of the spindle by spindle microtubules
Telophase
the last phase of mitosis: the chromosomes decondense, the nucleolus and nuclear envelope reform, the spindle depolymerizes and the phragmoplast
Cytokinesis
division of the protoplasm of a cell
Meiosis I
the first round of division where chromosome number per nucleus is reduced
Prophase I
similar t0 prophase of mitosis: nucleolus and nuclear membrane break down, centrioles separate, spindle forms, microtubules attach to centromeres and chromosomes condense; in addition there is leptotene: initiation of chromosome condensation; zygotene: pairing of homologous chromosomes (synapsis); pachytene: formation of the synaptonemal complex; diplotene: separation becomes visible; diakinesis: complete separation of homologs
Metaphase I
similar to metaphse of mitosis except that homologous pairs of chromosomes are involved
Anaphase I
similar to anaphase of mitosis except no division of centromeres occurs; one homolog is pulled away from the other in each pair which reduces the number of sets of chromosomes to haploid
Telophase I
similar to telophase of mitosis except telophase I and prophase II are often shortened or eliminated and full nuclei are not formed between meiosis I and II
Meiosis II
second division of meiosis and the two chromotids of one chromosome become independent chromosomes
Prophase II
similar to metaphase of mitosis
Anaphase II
similar to anaphase of mitosis
Telophase II
similar to telophase of mitosis
