Biology 11 - Ch 4 Review

7/23/2019 Biology 11 - Ch 4 Review

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4.1

Heredity – the passing of traits from parents of ospring

Genetics – the branch of biology dealing with heredity and variation of

inherited characteristics

Deoxyribonucleic acid D!"# – a molecule that carries genetic information in

cells

Gene – a segment of D!" molecule that codes for a particular trait$ found at

a speci%c location on a chromosome

&ocus – the location of a gene on a chromosome

'exual reproduction – the production of ospring from the fusion of ( sex

cells usually from ( dierent parents#$ the genetic ma)eup of the ospring is

dierent from that of either parent

*olyploid – having more than two sets of chromosomes$ many plants are

polyploids

"sexual reproduction – the production of ospring+s from a single parent+ the

genetic ma)eup of the ospring is identical to that of the parent

, DNA is the entire double stranded helix- Chromosome is one of the

strands- Genes are one part of the chromosome, hromosomes vary in number- shape and size from species to

species, Haploid cells are the half the normal number of chromosomes

, Diploid cells are ( sets of chromosomes

'exual reproduction!umber of parents ( parents/esulting ospring Genetic ma)eup that is dierent from both

parents"dvantage Disadvantage, 0ore genetic

variation, spring are

dierent from

parents

, rganisms must have speciali2ed

organs for sexual reproduction, 0ating rituals can attract predators, spring might inherit a combination

of genetic info ma)ing them wea) and

unable to survive

"sexual reproduction!umber of parents 'ingle parent/esulting ospring ( genetically identical daughter



cells to parent"dvantage Disadvantage, *arent does not have to %nd a

mate, Direct and invariable

, 3ncreased chances of

mutation, spring compete for food

, nfavorable conditions canwipeout entire colonies

4.(

ell Division

1. 3nterphase

, ell have ( sets of chromatin D!"#5 *aternal D!" and 0aternal D!"

, ell preform normal function growth- digestions excretion#

, ell grows then prepares to divide

, 678 of cell+s life

(. &ate 3nterphase

, Chromatin replicates

9. *rophase

, !ucleolus : nuclear membrane disappear

, entrioles start to move to poles

, Chromatin stands coil getting shorter and thic)er

, now called Chromatid

, 3dentical Chromatids ;oin to form chromosomes

- %rst signs are when chromatin turn to chromatid

4. 0etaphase

, hromosomes line up at e<uator

, entrioles start to ma)e spindle %bres

, 'pindle %bres attach to the centromere

=. "naphase

, 'pindle %bres attach to centromere of each chromosome pulling them

apart

, identical chromatids move to opposite poles

, same number and )ind of chromosome are found ate each pole

>. ?elophase

, !uclear membrane encloses new set of chromatin

, ytoplasm of the cell begins to divide as cell membrane pinches

inward

, 'pindle %bres dissolve



@. yto)inesis

, cell completely divides into two new cells

A. 3nterphase

, ( identical BdaughterC cells with the same D!" in the nucleus

hy do cells divide – 4 main reasonsE

1. ells must grow mitosis#

, all living things grow in si2e or number

, increase si2e means decreased surface areaFvolume ratio

, cells respond to this by cell division and ma)ing new cells

(. 0aintenance mitosis#

, cells age and die

, cells are lost

, new cells are produced to ta)e their place

9. /epair mitosis#

, cells become damaged- and new cells must be produced to replace

old- worn - and damaged cells

4. /eproduction meiosis#

, sex cells gametes# are produced to enable sexual reproduction

0eiosis

*urpose – to create sex cells for sexual reproduction

/esult – sperm or egg cell gamete# containing half the genetic information

chromosomes#

, Humans – eggs and sperm have (9 chromosomes combine in

fertili2ation to form human 2ygote 4> chromosomes#, 4 sperm cells are produced from meiosis, 1 egg cell is produced and 9 polar body disintegrate from meiosis

here

, nly in sex organs

, Somatic cells – all other cells that undergo mitosis

Diploid – full number of chromosomes (n#

Haploid – half the number of chromosomes n#

Divisions

, 0itosis has 1 division *0"?#



, 0eiosis has ( divisions *0"?#1 and *0"?#(

4.9Gamete – a sex cell$ includes sperm cell in males and egg cells in female

ertili2ation – the formation of a 2ygote by ;oining together of two gametes

ygote – a cell produced by the fusion of two gametes

0eiosis – a single cell division in which the resulting daughter cells have half

the number of chromosomes as the parent cell$ results in the formation of

gametes or spores

Homologous chromosomes – matching pairs of chromosomes- similar in si2e

and carrying information for the same genes

?etrad – a pair of homologous chromosomes each with ( sister chromatids

'ynapsis – the physical pairing up of homologous chromosomes during

prophase 1 of meiosis

rossing over – the exchange of chromosome segments between

homologous pairs during synapsis

Gametogenesis – the formation of genetic variable sex cells in meiosis (

'permatogenesis – the production of mature sperm cellsogenesis – the production of mature egg cells

Iaryotype – the chromosomes that dier in males and females of the same

species- the combination of sex chromosomes determines the sex of the

ospring

'ex chromosomes – chromosomes that dier in males and females of the

same species$ the combination of sex chromosomes determines the sex of

the ospring

Autosomes – non,sex chromosomes

, ?wo )ey processes that occur in sexual reproduction are the formation

of haploid sex cells which contain genetic information from both

parents and fertili2ation sex cells ;oin to produce a 2ygote#



, Dierence between 'ister chromatids and homologous chromosomes

actor 0itosis 0eiosis ?ypes of cells involved 'omatic – cells that

undergo mitosis

Gametes

!umber of divisions ina complete process

1 (

!umber of duplications

of chromosomes

1 1

!umber of cells

resulting from one

cycle

( 4

hromosome number

of parent cell

(n (n

hromosome number

of resulting daughter#cells

(n n

/ole of resulting cells hatever the function

of the parent cell

/eproduction – pass the

genetic informationunction of Division

process

Grow- 0aintenance-

/epair

/eproduce

4.4

!on,dis;unction – the failure of homologous chromosomes to move to

opposite poles of the cell during meiosis$ results in an abnormal number of

chromosomes in the daughter cells

?risomy – a chromosomal abnormality in which there are these homologous

chromosomes in place of a homologous pair

0onosomy – a chromosomal abnormality in which there is a single

chromosome in pace of a homologous pair



Down syndrome – a chromosomal abnormality in which an individual has 9

copies of chromosome number (1$ also referred to as trisomy (1

*renatal testing – testing for a genetic order that occurs prior to birth

!on,dis;unction diseases

Down syndrome ?risomy (1 ?urner syndrome ne J chromosome and no K

chromosomeIlinefelter syndrome ?wo J and one K chromosomes*atau syndrome ?risomy 19Ldwards syndrome ?risomy 1A

, Happens when gametes produced have (( or (4 chromosomes instead

of (9, ?risomy 2ygote has 4@ chromosomes, 0onosomy 2ygote has 4= chromosomes, !ormal 2ygote has 4> chromosomes

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Biology 11 - Ch 4 Review