Ch 3 & 4 Flashcards Preview

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Flashcards in Ch 3 & 4 Deck (65):
1

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

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Intrinsic proteins

proteins partially immersed in the lipid bilayer; differ in size, shape and location of hydrophobic, lipid soluable regions

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Extrinsic Proteins

AKA peripheral proteins that are located outside the membrane

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Hydrophilic Domains

loves water; can mix, dissolve in and interact with water; associate mostly with phospholipid phosphates and water

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Hydrophobic Domains

hates water; does not mix with or repels water; associates mostly with fatty acids and allows proteins to sink

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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

7

Glycoproteins

a protein with sugar attached (short chains less than ten sugars long)

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Vesicles (lumen)

Vesicle: small space enclosed by a membrane
Lumen: interior of a vesicle

9

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

10

Endocytosis

when material is absorbed into a cell by invagination in the plasma membrane, then it pinches and shits to form a vesicle

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Selectively Permeable

some substances cross the membrane more easily and rapidly than others

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Facilitated Diffusion

when large intrinsic proteins across the membrane assist in the movement of charged substances and act as hydrophillic channels

13

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

14

Protoplasm

all the substance of a cell not including the cell wall (single cell=protoplast); mass of proteins, lipids, nucleic acids and water

15

Plasma membrane

the membrane that covers the surface of the protoplasm; used for protection: impermeable to harmful substances and permeable to beneficial ones

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Nucleus

stores the organism's genetic information; contains DNA, involved in inheritance, metabolism control and ribosome synthesis

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Nucleoplasm

located in the nucleus DNA; substance of a cell nucleus: histones, RNA, enzymes, nucleic acids, water

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Nuclear envelope

surrounds the nucleus and composed of an outer membrane and an inner membrane; separates nuclear material from the rest of the cell

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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

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Nucleolus

Organelles in the nucleus where ribosomal RNAs are synthesized and assembled into ribosomal subunits

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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

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Cytoplasm

consists of nucleus, vacuoles and cytoplasm

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Mitochondria

eukaryotic organelles that carry out cell respiration

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Plastids

organelles only in plant cells

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Chloroplasts

chlorophyll-rich plastids that carry out photosynthesis

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Amyloplasts

plastids that store starch

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Chromoplasts

plastids that contain red or yellow pigments located in flowers and fruits

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Leucoplasts

colorless plastids; can be involved in various types of synthesis

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Endoplasmic Reticulum

narrow tubes and sheets of membrane that form a network throughout the cytoplasm

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Rough Endoplasmic Reticulum

ribosomes attached to the ER; involved in protein synthesis

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Smooth Endoplasmic Reticulum

no ribosomes; involved in lipid synthesis

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Dicytosomes

stack of thin vesicles held together in a flat or curved formation

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Microbodies

vesicle-like organelles that isolate reactions that either produce or use the dangerous compound peroxide, H2O2 called photorespiration

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Peroxisomes

detoxification of harmful products of photosynthesis and are closely associated with chloroplasts

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Glyoxysomes

involved in respiring stored fatty acids into sugars

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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

37

Microfilaments

composed of actin; used for structure and in the movement of organelles other than flagella, cilia or chromosomes

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Cell wall

provides strength and protection to the protoplasm; structure

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Primary cell wall

thin wall on all plant cells except some sperm cells; formed during cell division

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Secondary cell wall

in some plant cells; formed after cell division; located interior to the primary wall and typically impregnated with lignin

41

Genome

entire complex of genes

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Chromosome

thousands of genes in a linear sequence

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Histones

special class of proteins complexed with DNA that provides structure and protection

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Centromere

chromosomes that have a structural feature and located near the center of the chromosome

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Telomere

caps the end of the chromosome

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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

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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

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S Phase

DNA replication; the genes in the nucleus are replicated

49

Endoreduplication

repeated synthesis (replication) of nuclear DNA in the absence of cell division

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G2

part of interphase between the synthesis of DNA and the beginning of nuclear division; cells prepare for division

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Mitosis

duplication division

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Prophase

first phase of mitosis: the nucleus and nuclear membrane break down, the chromosomes condense and the spindle forms

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Metaphase

second phase of mitosis: the chromosomes move to the center of the spindle, the metaphase plate

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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

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Telophase

the last phase of mitosis: the chromosomes decondense, the nucleolus and nuclear envelope reform, the spindle depolymerizes and the phragmoplast

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Cytokinesis

division of the protoplasm of a cell

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Meiosis I

the first round of division where chromosome number per nucleus is reduced

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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

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Metaphase I

similar to metaphse of mitosis except that homologous pairs of chromosomes are involved

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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

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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

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Meiosis II

second division of meiosis and the two chromotids of one chromosome become independent chromosomes

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Prophase II

similar to metaphase of mitosis

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Anaphase II

similar to anaphase of mitosis

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Telophase II

similar to telophase of mitosis