Campbell Biology: Review for Chapters 12, 13, 16, 17 Flashcards

1. DNA doesn't grow with the cell, so as the cell gets larger, it demands more of DNA. To reduce strain, a cell must not grow anymore

2. Cells lose efficiency if too large because waste and nutrients do not move across the cell membrane.

The "in between growth of a cell". There are 3 parts: G1, S, G2

Phase of cell growth.

Cell increases in size.

Cell synthesizes new proteins and organelles

DNA replication.

DNA is synthesized and chromosomes are replicated.

2x the DNA

Preparing for cell division.

Shortest of the phases

organelles and molecules for division are produced

It is the cell division

follows interphase

produces 2 daughter cells. Consists of mitosis and cytokinesis

1st stage of cell division. It's the division of the cell nucleus. There are 4 phases

Usually the longest

genetic material inside nucleus condenses and duplicated chromosomes become visible.

outside the nucleus, spindles begin to form

Where duplicated DNA molecules attach along their length

Each DNA strand in the duplicated DNA chromosome

Where spindles extend from in animal cells.

Usually the shortest phase.

sister chromatids line up in the middle of the cell.

centrioles are at opposite ends, spindles connect to the centromes

Sister chromatids separate and move apart.

each sister chromatids is now considered an individual chromosome

chromosomes move to opposite ends of the cell

anaphase ends when the movements stops and the chromosomes are completely separated.

Chromosomes begin to spread into tangle of chromatin

nuclear envelope reforms around each cluster of chromosomes

spindles begin to break a part

nucleus becomes visible in each daughter cell

mitosis is complete

Result of mitosis

splitting of 1 cell into 2.

Animal cells get furrows, and cytoplasm is eventually pinched into two equal parts. In plant cells, first a cell plate forms. Nucleus separates. Then a cell wall forms.

All the DNA in a cell

Chromosomes

Complex of DNA & protein that condenses during cell division

Unreproductive cells

46 chromosomes!

Reproductive cells

have 1/2 as many chromosomes as somatic cells

they have 23 chromosomes!

Most cells are in this phase. These cells are not replicating. Some cells never leave this phase! Like Nerve cells, heart cells.

Array of short microtubules extends from each centrosome

Centrosomes

spindle microtubules

the asters

proteins attached to centromere that links sister chromatids to mitotic spindle

part of the mitotic spindle

Provides the stop / go ahead signal that tells a cell to split, or not to split.

cyclin dependent kinase, adds phosphate to a protein), along with cyclins, are major control switches for the cell cycle, causing the cell to move from G1 to S or G2 to M.

Cyclin & Cyclin-dependent kinases (cdks) (this is an enzyme)

from G2 phase to M phase.

cancer cells from Henrietta that never stop replicating. They are used in research

It does not receive any signals to stop. It is uncontrollable regulation.

binary fission

cell division in prokaryotes

the chromosome replicates and then 2 daughter chromosomes actively move apart.

the plasma membrane pinches inward, dividing the cell in 2

the scientific study of heredity and variation

the transmission of traits from one generation to the next

is demonstrated by the differences in appearance that offspring show from parents and siblings

a gene's specific location on a certain chromosome

reproductive cells (sperm & egg)

Gametes are Haploid! (23 chromosomes)

a single individual passes genes to its offspring without the fusion of gametes

the generation to generation sequence of stages in the reproductive history of an organism

*males are always in life cycle. females exit at menopause

From conception to time one reproduces!

23 pairs

23 from mom & 23 from dad

the two chromosomes in each pair of somatic cells

* chromosomes in a homologous pair are the same length and carry the same inheritable traits

ordered display of the pairs of chromosomes from a cell

the chromosomes in a human that are not the sex chromosomes

has 2 sets of chromosomes. (2n)

for humans - the diploid # is 46 (2n = 46)

somatic cells are diploid

diploid to haploid

4

Meiosis I results in 2 haploid daughter cells with replicated chromosomes

Meiosis II results in 4 haploid daughter cells with unreplicated chromosomes

Mitosis - Interphase

Mitosis - prophase

anaphase - mitosis

metaphase - mitosis

mitosis - telophase

mitosis - cytokinesis

The homologous chromosomes in Meiosis 1, each a pair of sister chromatids, join up to form a tetrad

x shaped regions in Meiosis 1, where crossing over occurs

breaking & rejoining at the chiasma in Meiosis 1

tetrads

homologous chromosomes

4 non-identical daughter cells

each with a HAPLOID set of unreplicated chromosomes

homologous chromosomes loosely pair up, aligned gene by gene

1. synapsis & crossing over in Prophase 1 (homologous chromosomes physically connect and exchange information
2. in metaphase, there are tetrads instead of individual replicated chromosomes
3. Anaphase 1 homologous chromosomes separate, not sister chromatids

during interphase

Mitosis = 1

Meiosis = 2

2 - each are identical to the parent cell, with the same number of chromosomes

4 - each haploid; genetically different from parent cell AND each other

is one of two or more versions of a gene. An individual inherits two alleles for each gene, one from each parent.

1. independent assortment of chromosomes
2. crossing over of chromatids
3. random fertilization

1. they orient randomly at metaphase 1
2. either the maternal or paternal can go to the daughter cell

recombinant chromosomes

C - G

T - A

deoxyribose

ribose

DNA: double strand, has thymine (t), and deoxyribose

RNA - single strand, has uracel (u), and ribose

They inject their DNA into a host cell in order to replicate and produce more.

A bases = T bases & G bases = C bases

Example:

A = 10, Thus T = 10

C = 20, thus G = 20

Plug & Solve:

A+C = T + G

10+20 = 10+20

As long as the equation equals, then the variables above work in the combination given. Example of NOT working:

A+T = C+G

10+10 = 20+20

hydrogen bond

Purine with a pyrimidine

at the origin of replication

It can only elongate in the 5 prime - 3 prime direction

both

located at each end of the replication bubble. This is where new DNA strands are elongating.

are enzymes that untwist the double helix at the replication forks

bind to and stabilize single stranded DNA until it can be used as a template

corrects overwinding ahead of replication forks by breaking, swiveling, and rejoining DNA strands

3

1. A primer is a strand of short nucleic acid sequences (generally about 10 base pairs) that serves as a starting point for DNA synthesis. It is required for DNA replication because the enzymes that catalyze this process, DNA polymerases, can only add new nucleotides to an existing strand of DNA.

enzyme starts an RNA chain and adds RNA nucleotides one at a time using the parental DNA as a template

The primer is short - and the 3' end serves as the starting point fro the new DNA strand.

catalyze the elongation of new DNA at a replication fork.

Most require a primer & DNA template strand

each nucleotide that is added to a growing DNA strand

5' to 3' direction BECAUSE nucleotides are added only to the free 3' end of a growing strand

leading strand

lagging strand

synthesize the lagging strand segments which join them together through DNA Ligase

repair enzymes correct errors in base pairing

chemicals, radioactive emissions, X-rays, UV light, and certain molecules (like in cigarette smoke)

a nuclease cuts out and replaces damaged stretches of DNA

postpone the erosion of genes near the ends of DNA

*Like junk DNA, no specific coding for function

*May be connected to how we age

enzyme that catalyzes the lengthening of telomeres in germ cells

DNA molecule; proteins

complex of DNA and protein, found in the nucleus of eukaryotic cells

Organized in fibers

They are the sites of translation.

they consist of rNA and proteins. They are assemble proteins of the cell;

free floating or bound

Uracil

genotype & phenotype

genetic make up of an organism

observable differences of an organism determined by genetics and environmental factors

Alternative forms of the same gene that occupy the same location on a chromosome.

*At any given locus, there are 2 (1 on each chromosome in the pair) – you get 1 a from your mother and 1 from your father.

bridge between genes and the proteins for which the code

the synthesis of RNA, directed by DNA - this produces mRNA

Messenger RNA

synthesis of a polypeptide from amino acids, under the direction of mRNA

the concept that cells are governed by a cellular chain of command

DNA --> RNA --> to protein

DNA ---> mRNA ---> Ribosome

DNA ---> Pre mRNA ---> mRNA ---> leave nucleus ---> ribosome ----> then to protein

RNA synthesis is catalyzed by RNA Polymerase, which pries the DNA strands apart and hooks together the RNA nucleotides

The DNA sequence where RNA polymerase attaches

They signal the transcriptional start point

stretch of DNA that is transcribed ; a gene

1. Initiation

2. Elongation

3. Termination

mediate the binding of RNA polymerase and the initiation of transcription

1. as polymerase moves along the DNA, it untwists the double helix
2. nucleotides are added to the 3' end of the growing RNA molecule

Eukaryotes: the polymerase continues transcription after the pre-mRNA is cleaved from the growing RNA chain; the polymerase eventually falls off the DNA

1. They seem to facilitate the export of mRNA
2. They protect mRNA from hydrolytic enzymes
3. They help ribosomes attach to the 5' end

5' cap at one end and a poly tail at the other

removes introns and joins the exons - creating an mRNA molecule with a continuous coding sequence.

[cap] - [intron] - [exon] - [intron] - [exon] - [AAAA]

junk DNA. They don't code for anything

hold the code on mRNA. Left in sequence to be read after the introns are spliced out

made of a variety of proteins & several small nuclear ribonucleoproteins (snRNPs) that recognize the splice sites

can make multiple proteins from 1 gene depending on what is spliced out of the sequence

catalytic RNA molecules that function as enzymes and can splice RNA

1. portable - can leave the nucleus
2. edited - (processed; only exons)
3. multiplicable (can make multiple mRNAs at a time
4. Temporary - mRNA degrades when need passes

Genetic Code

How information is ordered in RNA that is used to translate what protein should be made.

Codons are grouped in 3's

**determines what protein is to be made

Transfer RNA - brings the correct Amino Acid to the Codon

on the tRNA. Its the complementary to the codon on the mRNA

3

P

A

E

a = holds the tRNA that carries the next Amino Acid to be added to the chain

p = holds the tRNA

e = exit site from which tRNA leaves

they function in the cytosol

endomembrane system OR they are secreted from the cell

1. base-pair substitutions

2. base - pair insertions or deletions

replaces one nucleotide and its partner with another pair of nucleotides

have no effect on the amino acid produced by a codon because of the "extra" 3rd spot on the codon

still code for an amino acid - but not the right one

bad! these change the amino acid codon into a stop codon. No proteins are then made

stating that when two or more characteristics are inherited, individual hereditary factors assort independently during gamete production, giving different traits an equal opportunity of occurring together.