Topic 4
centrioles are organelles that do NOT have...
a lipid bilayer
animal cells depend on ___ to complete cytokinesis
actin filaments
a type of transport of a solute across a membrane, up its concentration gradient, using protein carriers driven by the expenditure of chemical energy is known as ___
active transport
the type of transport that is specific, which requires specific carrier molecules and energy is ___
active transport
peptidoglycan of the bacterial cell wall contains a carbohydrate matrix linked together by short chains of ____
amino acids
If a cell does not pass the G1 checkpoint..
apoptosis may occur
a semi-fluid matrix called the ____ occupies the area between the nucleus and the plasma membrane
cytoplasm
____ is the net movement of substances to regions of lower concentration
diffusion
a distinctive feature of eukaryotes is the organization of their chromosomal DNA which is tightly packaged with proteins into a membrane-bound structure called a __
nucleus
chromosomal hereditary material is packaged in this organelle in eukaryotic cells but not in prokaryotic cells which is ___
nucleus
what is the repository of the genetic information that directs all of the activities of the cell?
nucleus
the interior of eukaryotic cells contain numerous membrane-bound structures called ____
organelles
what does not occur 2 separate times during meiosis? a. separation of genetic material b. production of daughter nuclei c. pairing of homologous chromosomes CorrectPairing of homologous chromosomes occurs only once during meiosis. d. spindle formation
pairing of homologous chromosomes
the lipid layer that forms the foundation of cell membranes is primarily composed of molecules called ___
phospholipids
nucleolus of the nucleus is the site of _____
ribosome assembly
osmosis can only occur if water travels through the ___
semi permeable membrane
which of the following does not occur during meiosis I? a. separation of sister chromatids CorrectSeparation of sister chromatids occurs during meiosis II. b. formation of two daughter nuclei c. synapsis d. separation of homologous chromosomes
separation of sister chromatids
which of the following events occurs last during meiosis? a. pairing of homologous chromosomes IncorrectSeparation of sister chromatids occurs last in the events listed. b. crossing over c. separation of sister chromatids d. interkinesis
separation of sister chromatids
orderly separation of duplicated chromosomes is controlled by the ___
spindle
which of the following does not occur during G1: preparation for DNA replication, growth, synthesis of proteins for mitosis, doubling of organelles
synthesis of proteins for mitosis does not occur during G1
what are the requirements of facilitated diffusion?
the carrier molecule must be specific to the molecule being transported and the direction of movement is with the concentration of gradient
what is cancer?
uncontrolled cell division
a species that has 3 sets of homologous chromosomes can have up to ___ different combinations of chromosomes in the gametes
8
list the events of mitosis
1. sister chromatids condense 2. nuclear membrane breaks up 3. sister chromatids align on the metaphase plate 4. sister chromatids separate 5. cleavage furrow forms
Meiosis I produces ____ and meiosis II produces _____
2 haploid cells , 4 haploid cells
humans have ____ different types of autosomes
22
which of the following statements are correct? a. In actively dividing cells, the S and G2 phases only are known as interphase. b. During G2 phase, the cell grows and copies its chromosomes in preparation for cell division. c. When the S phase of the cell cycle is finished, a cell actually has twice as many chromatids as the number of chromosomes in the G1 phase. Correctcorrect d. The cell cycle is a sequence of replication and division that produces a new cells. e. The phases of the cell cycle are G1, S, and M phases.
C. When the S phase of the cell cycle is finished, a cell actually has twice as many chromatids as the number of chromosomes in the G1 phase.
plant cells depend on the ____ to complete cytokinesis
Golgi apparatus
chromosomes are replicated during the ___ phase
S
the genetic material of which kind of cells is included in a single, circular molecule of DNA devoid of any histone proteins?
bacteria
the G2 checkpoint prevents the cell cycle from continuing until...
both DNA is completely replicated and damage to DNA can be repaired
a tetrad is composed of....
both four chromatids and replicated homologous chromosomes
chromosomes can be condensed into compact structures, visible with the light microscope, but usually only during..
cell division
what is not present in all eukaryotic cells?
cell wall
what is not part of the mitotic spindle apparatus in plants?
centriole
DNA duplicates as ____
chromatin
what process occurs during meiosis that is not involved in the orderly separation of chromosomes but in creating variation among chromatids?
crossing-over
cytokinesis includes both the...
division of cytoplasm and separation into daughter cells
in eukaryotes, mitochondria are the organelles primarily involved in...
energy release/capture
carrier mediated transport is also called ____
facilitated diffusion
the type of diffusion that is specific and passive, and which becomes saturated if all of the protein carriers are in use is _____
facilitated diffusion
T/F: sister chromatids separate during telophase
false
which leads to variation in offspring?: fertilization, cytokinesis, formation of Barr bodies, interkinesis
fertilization
meiosis results in ____ daughter cells which are genetically ____
four / different from each other
normal human gametes are ____
haploid
membrane proteins are not very soluble in water, because they possess long stretches of non-polar amino acids that are...
hydrophobic
sister chromatids are...
identical to each other
sister chromatids first appear during ____ of the cell cycle
interphase
the majority of time in the cell cycle is spend during ___
interphase
____ are a type of internal signal molecule used in controlling the cell cycle
kinases
ribosomes are.....
large molecular aggregates of protein and RNA
why must the life cycle of sexually reproducing species alternate between haploid and diploid stages?
meiosis must occur at some point in the life cycle to prevent a doubling of chromosomes in each generation
plasma ____ encloses the cell and separates its contents from the surroundings
membrane
for the process of diffusion to occur, molecules must...
move from areas of high concentration to areas of lesser concentration until an equilibrium is reached
during metaphase, chromosomes are....
much shorter than they were in interphase
when sister chromatids fail to separate during meiosis, this is called ____
nondisjunction
which of the following is not bounded by membranes? a. microbody b. nucleus c. Golgi body d. endoplasmic reticulum e. nucleoid
nucleoid
in mitosis, the main difference between plant and animal cells is that...
plants produce a cell plate to segregate daughter nuclei while animals form a cleavage furrow
meiosis leads to variation in offspring by....
producing gametes with all possible combinations of chromosomes
nuclear pores apparently permit the passage of only...
protein inward and outward but RNA only outward
the plasma membrane is a thin sheet of lipid embedded with ____
proteins
one of the main functions of meiosis is to....
reduce the number of sets of chromosomes