Chapter 11-14

animal and plant cells have…

cell junctions

cell junction

directly connects cytoplasm of adjacent cells

In local signaling animal cells may communicate by direct contact or…

cell-cell recognition

in many other cases animal cells communicate using…

local regulators

local regulators are

messenger molecules that travel in only short distances

in long distance signaling plants and animals use chemicals called…

hormones

ligand is…

a signal molecule

the binding between the signal molecule and the receptor is…

highly specific

A shape change in a receptor is often the…

initial transduction of the signal

a G protein-couples receptor (GCPR) is…

a plasma membrane receptor that works with the help of G protein

GCPR based signaling systems are…

extremely widespread, diverse and regulate almost all know physiological processes

Many signaling molecules like….use GCPR

epinephrine and opioids

Receptor tyrosine kinases

membrane receptors that attach phosphates to tyrosines

A receptor tyrosine kinase can trigger…

multiple signal transduction pathways at once

GCPR’s only active ______ pathway

a single transduction

Receptor Tyrosine

constitute a class of receptors that play an important role in cancer progression

Ion channel receptor acts as a….

gate when the receptor changes shape

when a signal molecule binds as a ligand to the receptor the gate allows specific…

ions through a channel into the receptor

Specific Ions the gate allows through

Na+ and Ca^2+

signal transduction usually involves…

multiple steps

multistep pathways can ____ a signal

amplify

the molecules that relay a signal from a receptor to response are mostly…

proteins

the receptor _____ another protein

activates

at each step the signal is transduced into…

a different form, usually a shape change

in many pathways the signal is transmitted by a cascade of…

protein phosphorylations

protein kinases transfer…

phosphates from ATP

protein phosphates remove…

the phosphates from proteins (dephosphorylation)

The phosphorylation and dephosphorylation system acts as a…

molecular switch turning activities on and off

many signaling pathways regulate the…

synthesis of enzymes or other proteins

the synthesis of enzymes or other proteins usually…

turns genes on or off in the nucleus

most cell division results in…

daughter cells with identical genetic information

A special type of division produces…

non-identical daughter cells

non-identical daughter cells

gametes or sperm and egg cells

All the DNA in a cell constitutes the cells…

genome

A genome can consist of a single DNA…

molecule or a number of DNA molecules

DNA molecules in a cell are packed into…

chromosomes

Somatic cell

non-reproductive cell

somatic cells have…

two sets of chromosomes

gametes

reproductive cells: sperm and egg

gametes have…

half has many chromosomes as somatic cells

Eukaryotic chromosomes consist of…

chromatin

chromatin

a complex of DNA and protein that condenses during cell division

In preparation for cell division DNA is…

replicated and the chromosomes condense

Each duplicated chromosome has…

two sister chromatids which separate during cell division

centromere

narrow “waist” of the duplicated chromosome, where two chromatids are most closely attached

mitotic phases

Mitotic (M) Phase- mitosis and cytokinesis

Mitosis-the division of the nucleus

Cytokinesis-the division of the cytoplasm

Interphase

cell growth and copying of chromosomes in preparation for cell division

Interphase is about…

90% of the cell cycle

Interphase can be divided into subphases…

G1 phase- “first gap”

S phase- “DNA Synthesis”

G2 phase- “second gap”

The cell grows during all three phases but….

chromosomes are duplicated only during the S phase

Mitosis is divided into five phases…

Prophase

Prometaphase

Metaphase

Anaphase

Telophase

cytokinesis is underway by…

late telophase

the miotic spindle is an…

apparatus of microtubules that controls chromosome movement during mitosis

During prophase assembly of spindle microtubules begin in the…

centrosome

centrosome

the microtubule organizing center

the centrosome replicates forming…

two centrosomes that migrate to opposite ends of the cell as spindle microtubules grow out from them

aster

a radical array of short microtubules

an aster extends from..

each centrosome

The spindle includes the..

centrosomes, spindle microtubules, and asters

During prometaphase some spindle microtubules attach to the…

kinetochores of chromosomes and begin to move them

at metaphase the…

chromosomes are lined up at the metaphase plate

metaphase plate

the midway point between the spindles two poles

In anaphase, sister chromatids separate and move along the…

kinetochore microtubules toward opposite ends of the cell

In animal cells, cytokinesis occurs by a process called…

cleavage forming a cleavage furrow

In plant cells ______ forms during cytokinesis

cell plate

The cell cycle control system is regulated by..

both internal and external controls

for many cells the G1 checkpoint seems to be..

the most important one

if a cell receives a go-ahead signal at the G1 checkpoint it will usually…

complete the S, G2, and M phases and divide

If the cell does not receive the go-ahead signal, it will…

exit the cycle, switching into a nondividing state called the G0 phase

ex. of external signals

density-dependent inhibition

density-dependent inhibition

crowded cells stop dividing

Most animal cells exhibit…

anchorage dependence

anchorage dependence

cells must be attached to a substratum in order to divide

cancer cells exhibit neither…

density-dependent inhibition nor anchorage dependence

Genes are passed to the next generation through…

reproductive cells (gametes-sperm and eggs)

Each gene has a specific location on a certain…

chromosome

locus

specific location for gene

one set of chromosomes is inherited from each…

parent

in asexual reproduction…

one parent produces genetically identical offspring by mitosis

clone

group of genetically identical individuals from the same parent

sexual reproduction

two parents give rise to offspring that have unique combinations of genes inherited from the two parents

human somatic cells have…

23 pairs of chromosomes

karyotype

ordered display of the pairs of chromosomes from a cell h

the two chromosomes in each pair are called….

homologous chromosomes (or homologs)

chromosomes in a homologous pair are the…

same length and carry genes controlling the same inherited charachers th

the sex chromosomes are called

X and Y

females have a homologous pair of…

X chromosomes (XX)

males have…

one X and one Y chromosome

autosomes

the 22 pairs of chromosomes that do not determine sex

each pair of homologous chromosomes includes…

one chromosome from each parent

Diploid Cell (2*n)* has…

two sets of chromosomes

A gamete contains a…

single set of chromosomes and is a haploid(*n*)

fertilization

union of gametes

zygote

fertilized egg

zygote has…

one set of chromosomes from each parent

the zygote produces…

somatic cells by mitosis and develops into an adult

meiosis is preceded by the…

replication of chromosomes

the two cell divisions result in…

four daughter cells

each daughter cell has only…

half as many chromosomes as the parent cell

synapsis

homologous chromosomes loosely pair up, aligned gene by gene