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