BIO Lab 1 Exam 2 DNA and Chromosomes lab10

DNA

deoxyribonucleic acid.

-All life as we know it uses it to store its design information and to reproduce.

-has sugar-phosphate backbone held together by covalent bonds

-double stranded

-bases held together by hydrogen bonds

-two complementary strands of ___ coiled together to form a double helix

Genes

sections of DNA that usually code for a protein product

-codes for a functional RNA molecules

-encodes amino acid sequence

chromosomes

eukaryotic cell contains nucleus which contains linear pieces of DNA. DNA are wound up around proteins forming this

46

Different Eukaryote species may have a different number of chromosomes. Humans have _ _ chromosomes.

-Humans are diploid meaning that half of their chromosomes come from mom and half dad

-2n

zygote

A mother contributes a set of 23 in her haploid egg and a father contributes a set of 23 in his haploid sperm to make a _____

-fertilized diploid egg

homologous pair

Each chromosome has different genes. For example, perhaps chromosome #1 has genes #1-#1,000, while chromosome #2 has genes #1,001 - #2,000, and so on. Chromosomes of the same number from both parents are said to be a ….

-Each chromosome of a _________ ___ has the "same genes," or more precisely, directions for building the same proteins.

-not attached to each other except during very specific moments

Karyotype

image of an organism's chromosomes showing their different lengths and artificially placing homologous pairs next to each other to number them.

autosomal

22 chromosomes pairs are _________ (non sex) and one chromosome pair is the sex chromosome

locus

Genes that code for the same protein product are located in the same relative position on homologous chromosomes. The location of a particular gene on a chromosome is called the

alleles

Directions (gene’s DNA sequence) can differ between the chromosome you got from mother and father. Genes at the same locus for the “same” protein product that doffer in DNA sequence are

-different version of same gene

Genotype

combination of alleles an individual has for a particular gene locus

homozygous genotype

two identical directions for making the same protein (two of the same alleles)

heterozygous genotype

inherited different alleles from their parents

Genome

all of the genes in all of an organism’s chromosomes

-21,000- 25,000 genes

Cell division

Living organisms as well as the cells that compose tissues are capable of repro­duction and growth.

-New cells are produced whether for growth, repair, replecment, or forming a new organism.

-cellular and nuclear materials of somatic (body) cells are divided between daughter cells (structurally and functionally similar each other and parent cell)

Bacteria and Archaea

Which prokaryotic domains’ distribute exact replicas of genetic material is comparatively simple.

In Eukaryotes organisms like animals is more complex

Interphase

cells spend most their lives here

-has 3 stages

-DNA replicates and chromosomes duplicate into H shape pairs of sister chromatids

-sister chromatids are connected at the centromere

G1

primary growth phase

-cell recovers from pervious division, increases in size, and protein synthesizes proteins, lipids, and carbohydrates

-# of organelles increases

-centrosome that contain two centrioles which begin to develop during this phase

-major portion of life span

S phase

chromosome replicates to produce two daughter copies(sister chromatids)

-two copies remain attached at centromere

-not yet condensed

-some proteins and histones manufactured within nucleus and cytoplasm

-centrioles duplication completed

G2

further replication of membranes, microtubules, mitochondria, and other organelles

-newly replicated siter chromatids begin to coil and get more compact

mitosis

distribute identical sets of chromosomes from the parent cell to each of the daughter cells.

Prophase

first, longest, and most active stage of mitosis

-chromosomes progressively get more visible as they condense

-centrioles migrate towards opposite poles

-disintegration of nuclear envelope and nucleolus

-spindle fibers radiate from centrioles

Metaphase

centromere joining each pair of sister chromatids is attached to spindle fibers. Pairs eventually align midway between the centrioles (equatorial plane)

Anaphase

separation of sister chromatids from their centromere and movement of the chromatids as they are pulled back along the spindle of opposite poles

Telophase

final stage; resembles dumbbell; set of chromosomes at each end.

-spindle fibers are disassembled the nuclear envelope and nucleolus are reformed and organelles organized

Cytokinesis

division of cytoplasm

-cell is pinched and eventually two daughter cells completely formed.

-in plants: cell plate is formed in middle; then dividing the mother cell into two daughter cells

diploid cell is two daughter cells; both diploids with identical genomes and pairs of homologous chromosomes

end result of mitosis and cytokinesis

gametes

sexual reproduction requires the combining of _____ or sex cells

-23 chromosomes; haploid

Meiosis

process that produces gametes by reducing a cell in the diploid states to haploid

fertilization

sexual production is based up ______, the union of haploid male and female gametes to form a diploid zygote. The zygote possesses homologous chromosomes from each parent.

Prophase 1 Meiosis

homologous chromosomes pair up in process called synapsis and form tetrads

-exchange of genetic material by crossing over each other, making that sex cell unique

Metaphase 1 Meiosis

homologous pairs line up along the metaphase plate in double row

-independent alignment of chromosomes of maternal and paternal origin allows for the genetic diversity

-independent assortment

Independent alignment

chromosomes of maternal and paternal origin allows for the genetic diversity seen in families. In other words, for each homologous pair of chromosomes, it is a 50% chance whether the maternal chromosome will be on the left and the paternal chromosome will be on the right, and vice versa.

independent assortment

means that the inheritance of one pair of genes is independent of the inheritance of another. For example, homologous chromosome pair #4 will independently assort from pair #7; there is a separate 50% chance for each pair as to which member of the pair makes it into the gamete. Independent alignment and independent assortment contribute to the genetic diversity of offspring.

Anaphase 1

homologous chromosomes separate and migrate toward opposite poles.

-homologous chromosomes each have an allele for the same gene locus, alleles are segregating

- The combining of alleles from males and females during sexual reproduction contributes to the genetic diversity of offspring, which would not be possible without allele segregation during meiosis.

Telophase 1 Meiosis

sister chromatids reach the opposite poles and eventually form two new haploid cells but possess two sister chromatids in chromosomes

Meiosis 2

results in division of the sister chromatids from Meiosis 1

Prophase 2

attachment of the sister chromatids to the spindle

Metaphase 2

sister chromatids line up along the metaphase plate

Anaphase 2

sister chromatids are separated and migrate towards the centrioles

Telophase 2

results in the formation of four unique haploid daughter cells with one chromatid per chromosome