LAB2 Flashcards
why do somatic cells reproduce?
GRR - growth, replacement, repair
what is interphase?
time at which cell grows size, carries out normal metabolic activities, prepares for cell division
what is cell division?
series of events leading to production of two identical daughter cells from one parent cell
what happens in G1?
cell grows and conducts normal cellular functions, cell prepares for cell division by duplicating most organelles and other cytoplasmic materials
what happens in S phase?
DNA is replicated
what happens in G2?
enzymes and other proteins that will aid in mitosis produced, centriole replication complete
what happens in G0?
non-dividing stage, can never be replaced if they die
what kind of cells replace the types of cells that need continuous replacement?
stem cells, which can continuously divide
what cells go into G0 phase?
neurons and skeletal muscle cells
what happens in prophase?
- chromatin fibers condense into visible chromosomes
- nucleolus disappears, nuclear envelope breaks down
- centrioles pushed to opposite poles by lengthening microtubules
- spindle fibers form and asters visible around centrioles
what happens in metaphase?
microtubules of spindle fibers align the centromeres of each pair of chromatids at metaphase plate
what happens in anaphase?
- centromeres split and chromatids separate and move towards opposite poles
- chromatids now considered separate chromosomes
what happens in telophase?
- chromosomes at poles, uncoil into chromatin
- nuclear envelope and nucleolus reappear
- mitotic spindle break down
what happens in cytokinesis?
cleavage furrow during late anaphase grow as microfilaments contract and plasma membrane pushed inward until cytoplasm separated into two
what is the role of microtubules during prophase?
assembles and forms mitotic spindle that will later attach to kinetochores on the chromosomes
what is the role of microtubules during metaphase?
lengthen and align with centromeres of each chromatid pair at metaphase plate
what is the role of microtubules during anaphase?
split centromeres, drag chromatids to opposite poles
why do chromatin fibers condense before dividing?
to prevent tangling with itself when it moves around cell during mitosis
what is a blastula?
embryonic stage of development that occurs shortly after fertilization when embryo is undergoing rapid cell division
what is the plasma membrane?
physical barrier that surrounds each cell, separating it from environment and regulating which substances pass into and out of cell
what is selective permeability?
the ability to regulate the passage of materials into and out of cell
what is Brownian motion?
the ricocheting of molecules in gases and liquids off one another and changing direction with each collision due to kinetic energy that causes them to be in constant motion
how is equilibrium caused by Brownian motion?
collisions between molecules cause them to spread out and eventually reach an equal distribution in a container
what is diffusion?
movement of molecules from an area with high conc. of that molecule to an area of low conc of that molecule
what is the driving force behind diffusion?
kinetic energy present in the molecules
what variables cause diffusion?
- steepness of conc. gradient
- temperature
- mass/size of particles
- surface area
- distance of diffusion
- time
what is osmosis?
type of simple diffusion where water moves across a selectively permeable membrane from an area of high conc. of water to an area of low conc. of water
when does osmosis occur?
when a membrane is permeable to water but not to other substances present in the solution
what is hemolysis?
water rushes into a red blood cell and causes it to burst
what is crenation?
water rushes out of a red blood cell and causes it to shrink and shrivel up
what is the positive result for starch using iodine as a reagent?
deep purple/blue colour
what is the negative result for starch using iodine as a reagent?
yellow colour
what is the positive result for Cl- ions using AgNO3 as reagent?
white ppt.
what is the negative result for Cl- ions using AgNO3 as reagent?
no ppt. produced
what is the positive result for glucose using glucose strips?
any yellow-green or brown colour
what is the negative result for glucose using glucose strips?
aqua blue colour
