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85 Cards in this Set
- Front
- Back
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What is a cell? |
basic structural unit of the body; can perform basic functions of life.
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What are the components and function of the cell membrane?
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phospholipid bilayer, membrane proteins, membrane CHOs, microvilli. to communicate between inside of cell and outside of cell.
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What is the phospholipid bilayer composed of?
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phospholipids with phosphate heads which are hydrophilic and lipid tails which are hydrophobic.
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What are membrane proteins and their functions?
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(1) integral (transmembrane proteins), cross the membrane completely, form ion channels, transporters, and hormone receptors. |
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Where are membrane CHOs located and what are their function?
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on outer surface of lipid bilayer - bound to proteins or lipids. Used for cell to cell recognition and to anchor cells together.
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What is the function of microvilli on the cell membrane?
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to increase cell surface (by 5000x!)
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What is the cytoplasm?
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all cellular material between cell membrane and nucleus.
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What is found in the cytoplasm?
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cytosol and organelles.
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What is cytosol, it's function, and where is it found?
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gel-like intracellular fluid. mainly H2O. suspension of CHOs, proteins, lipids and dissolved ions. higher potassium concentration and lower sodium concentration than extracellular fluid. found in cytoplasm.
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What are organelles and what kinds are there?
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specialized cellular components. non membranous organelles which are in direct contact with cytosol, membranous organelles, which contain membrane bilayer to separate organelles from bilayer.
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What are ribosomes composed of, what are their function, where are they found?
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rRNA and proteins; site of protein synthesis, either floating free in cytosol or attached to rough ER.
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What are centrosomes and their function? What role is played in mitosis/meiosis?
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dense area of cytoplasm; organizes microtubules and cytoskeleton. forms spindle apparatus.
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What are centrioles and their function?
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pair of microtubules in centrosome. function uncertain.
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What is the cytoskeleton? What is it composed of? What is it's role?
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internal scaffolding of cell. protein filaments.determines cell shape; provides strength/flexibility, anchors organelles.
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What protein filaments is the cell cytoskeleton made up of?
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microfilaments (actin subunits, involved in cell motility/shape changes), intermediate filaments (tough protein filaments, maintain structure), microtubules (hollow tubes of tubulin. forms centrioles, spindle, cilia, flagella; move/secure organelles in cytosol).
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What is most abundant protein in cells?
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Actin = %15.
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What are mitochondria? it's functions?
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cellular power plant. site of ATP synthesis. contain their own DNA, RNA, proteins.
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What types of endoplasmic reticulum are there? What's the difference?
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Rough ER, Smooth ER. ribosomes attach to rough ER which therefore becomes the site of secretory lysosomal and membrane protein synthesis. Smooth ER don't have ribosomes and is continuous with RoughER. lipid and steroid hormone synthesis as well as drug/toxin detox.
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What is the Golgi apparatus and it's function?
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stacks of membrane disks. sorts, modifies, packages and delivers proteins and lipids to plasma membrane, lysosomes, or for secretion.
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What are lysosomes and their functions?
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"suicide sacs". filled with digestive enzymes. breaks down bacteria, old organelles, and cells.
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What is the nucleus?
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DNA containing control center of a cell.
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What are components of the nucleus?
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nuclear membrane, chromatin, nucleoli.
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What is the nuclear membrane?
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double bilayer which is continuous with the ER and contains many pores.
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What are the nucleoli?
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dark staining non membrane bound bodies inside nucleus. Sites of ribosome production.
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What are the chromatin?
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DNA and histone proteins.
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What forms are the chromatin found in?
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dispersed (not individually visible in non dividing cells) and condensed (individually visible in dividing cells).
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** What are somatic cells and their characteristics?
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all cells of the body except sex cells. diploid (2N), have 46 chromosomes. 22 autosomal pairs and 1 sex pair.
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** What is a gene?
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A functional segment of DNA on the chromosomes. Each contains instructions for synthesis of a protein.
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** Are autosomal chromosome pairs identical?
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No, they are equivalent. Identical in length, centromere position, have genes for the same traits but may have different versions of genes.
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** What is an allele?
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Different version of the same genes (blue eyes vs brown ones)
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What are the phases of the cell life cycle?
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Within interphase it is the G1 phase, Synthetic phase, and the G2 phase.
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What is the cell life cycle?
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series of changes a cell goes through from when it is formed until it reproduces. |
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What phase are cells that just stop dividing in?
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G0 phase.
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What happens in G1 phase?
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rapid cell growth, increased protein synthesis.
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What happens in Synthetic phase?
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DNA replicates, chromatin pairs held together by centromeres, kinetochores form on each centromere.
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What are kinetochores?
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proteins that are the site of attachment of spindle microtubules.
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What happens in G2 phase?
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additional growth and protein synthesis; production of enzymes and proteins needed for cell division.
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List the phases of a cell life cycle in order from most amount of time to least.
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G1 (8-10hrs), S (6-8hrs), G2 (4-6hrs)
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What is mitosis?
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division of nuclear material
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What is cytokinesis?
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division of cytoplasm.
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What are the phases of Mitosis?
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Prophase, Metaphase, Anaphase, Telophase.
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What happens in Prophase?
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- chromatin condense
- nuclear envelope fragments, nucleolus disappears - spindle apparatus forms from centrosomes found at cell poles - join to kinetochore proteins on each centromere |
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Metaphase?
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46 chromosomes line up on cell equator.
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Anaphase?
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-centromere splits = 92 chromosomes
-spindle pulls 46 chromosomes towards each pole - cytokinesis begins |
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Telophase?
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- spindle apparatus dissembles
- nucleolus reappears - nuclear envelope forms around each chromatid mass. - cytokinesis ends = cells split. |
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How does meiosis work?
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One 2N cell creates four 1N cells. In males this is 4 sperm cells, in females this is one ovum and 3 polar bodies. NOT A CYCLE.
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How are prophases of meiosis similar to mitosis?
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chromatin condense; nucleolus disappears; spindle apparatus forms from centrosomes and joins to kinetochore.
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How are anaphases of meiosis similar to mitosis?
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cytokinesis begins
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How are telophases of meiosis similar to mitosis?
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cytokinesis ends; spindle apparatus dissembles, nucleolus reappears.
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What is unique to meiosis?
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instead of chromosome pairs there are tetrads in meiosis I (23 pairs of pairs = 92 strands of chromosomes). At start of meiosis II there are 23 pairs (46 strands) in the 1N cells.
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What is interkinesis?
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an interphase-like period between meiosis I and meiosis II. THERE IS NO DNA REPLICATION.
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What are the results of meiosis?
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Four 1N gametes with 23 chromatin strands each. |
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How are sperm formed?
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1o spermatocyte turns into two 2o spermatocytes after meiosis I, and then into 4 sperm after meiosis II.
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How are eggs formed?
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1o oocyte turns into one 2o oocyte and one polar body (after meiosis I). The 2o oocyte is ovulated and ONLY IF fertilized completes meiosis II and becomes and ovum and a polar body.
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When does fertilization occur?
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After meiosis I of the 2o oocyte.
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What is a zygote?
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The fusion of male and female pronuclei (1N cells) which turns into a 2N cell (a zygote).
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What is the pre-embryonic period?
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germinal, first 2 weeks.
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What are the stages of the germinal period?
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zygote --> morula -->blastocyst
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What is a morula?
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After about 4-5 cell divisions, this is a solid ball of 16-32 cells (blastomeres) formed by mitotic divisions.
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What is a blastocyst?
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Morula hollows out; approximately 4 days after fertilization. Has chorion, trophoblast, blastophoel, and inner cell mass.
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When does implantation occur?
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5-7 days after fertilization. implants into endometrium of uterus.
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What is a trophoblast? What does it form?
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single layer of cells on outside of blastocyst. forms chorion and will provide nutrients to embryo.
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What is a blastophoel?
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fluid filled cavity of blastocyst.
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What is the inner cell mass of the blastocyst?
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future embryo.
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What happens in days 7-13 of early development?
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2 layered embryonic disk forms from inner cell mass. The epiblast and the hypoblast.
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What is the epiblast?
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forms in days 7-13 of early development. will give rise to amnion (with a fluid filled amniotic cavity) and 3 germ layers of embryo.
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What is the hypoblast?
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forms in days 7-13 of early development. Will give rise to yolk sac.
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When is the Embryonic Period of early development?
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Weeks 2-8
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What does the epiblast give rise to in the embryonic period?
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ectoderm, mesoderm, endoderm (3 germ layers) and amnion.
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What is ectoderm and what will it form in a human?
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one of the 3 germ layers formed from the epiblast; will form nervous system and epidermis of skin.
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What is mesoderm and what will it give rise to in a human?
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one of the 3 germ layers in embryonic period from the epiblast. will forms tissues such as muscle, bone, dermis, blood vessels.
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What is endoderm and what will it give rise to in a human?
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one of the 3 germ layers that are made from the epiblast in embryonic period. will form epithelial lining, and urinary, disgestive, respiratory, and reproductive systems + associated glands.
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What is the amnion?
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derived from the epiblast and surrounds embryo with amniotic fluid.
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What is the chorion?
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Derived from trophoblast cells. Forms fetal part of placenta.
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What is the yolk sac?
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derived from hypoblast (endoderm) and forms part of the gut, blood cells, and vessels.
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What is the allantois?
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outpocket of yolksac; forms umbilical cord and urinary bladder.
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What happens in weeks 4-8 of early development?
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general human characteristics and major organ systems become almost fully developed.
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When is the fetal period and what happens in it?
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weeks 9-40. growth and maturation of organs continues.
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What is a genotype?
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catalogue of person's genetic make up.
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What is phenotype?
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observable expression of genotype.
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What are homozygous alleles?
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same allele of a particular gene on homologous chromosomes; both express same version of the gene.
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What are heterozygous alleles?
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different alleles of the same gene on homologous chromosomes; each allele encodes a protein with different amino acid composition.
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What is a dominant allele?
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The gene expressed in the phenotype, regardless of other instructions from other alleles.
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What is a recessive allele?
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allele whose expression is hidden by the dominant allele.
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What is sex-linked inheritance?
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When the inheritance is determined by a gene on the X chromosome, since there's like nothing on the Y chromosome.
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