BIO Ch. 9-11

Alternate forms of a gene are called ____. The DNA sequences of _____ are highly similar, but different enough to produce alternative physical traits.

alleles

In plants, gametes are SPORES: repro cells that develop into new multicellular structures without fusion with another cell necessary. This is the haploid generation, which produces gametes. The resulting zygote becomes diploid generation This is ____________

alternation of generations

plants alternate between _____ and _____ 2 ANSWERS

Sporophyte, gametophyte

when one gene affects more than one phenotype Ex. sickle cell anemia SS is non-sickle cell Ss is heterozygous, has nonsevere symptoms ss is sickle cell, decreased ability to carry O2 in Red Blood Cells

pleiotropy

occurs during meiosis II when the sister chromatids fail to separate and both daughter chromosomes go into the same gamete.You get two normal gametes and two aneuploid gametes

secondary nondisjunction

Law of ______: Each individual has two factors for each trait The factors segregate (separate) during the formation of the gametes Each gamete contains only one factor from each pair of factors Fertilization gives each new individual two factors for each trait

segregation

Mendel's second law: During pollination process- only one trait from each parent passed on during pollination Law of ________= during gamete formation, alleles separate

segregation

females are more likely to CARRY ____ linked disorders

sex

genes carried on X chromosomes are ___ linked inheritance Ex. Red/green colorblindness hemophilia

sex

males are more likely to get ___ linked disorders

sex

_____ reproduction: haploid (n) (have half the chromosomes of the parent cell) gametes are produced during meiosis that subsequently merge into a diploid cell called a ZYGOTE

sexual

A ______ is an agent that influences the activities of a cell

signal

failure of chromosomes to separate. May result in gain or loss of chromosomes.

nondisjunction

TtPp can make ___ different possible gametes: TP, tp, Tp,tP

4

in spermatogenesis, you end up with ___ viable haploid sperm

4

the 2n number of chromosomes (because you have 23 pairs)

46

The phenotypic distribution for a dihybrid cross is _______

9:3:3:1

the correct # of chromosomes

Euploidy

Some cells don't do cell cycle, like nerve and muscle cells. They exit interphase and enter stage ____. No prep for cell division, just normal everyday processes. Don't leave ___ without proper signals form other cells/parts of body.

G0

the stage before DNA replication. "growth" phase. Cell recovers from previous division. Grows and increases number of organelles, gets materials for future DNA synthesis. Also continues to perform notmal functions: secretion, communication, respiration etc.

G1

stage from the completion of DNA replication to onset of mitosis. Cell synthesizes proteins that will assist in cell division. Microtubules form the mitotic spindle critical in M stage.

G2

The DNA in the chromosomes of eukaryotes has proteins called _____ that are involved in organizing chromosomes.

histones

Short rest period prior to second nuclear division in meiosis. Similar to interphase except no DNA replication because chromosomes already duplicated.

Interkinesis

(Mitotic) STAGE: following interphase, cell enters this stage. Includes mitosis (nuclear division) and cytokinesis (division of cytoplasm). During mitosis, daughter chromosomes are distributed by the mitotic spindle to two daughter nuclei.

M

DNA is replicated in ___ phase of the cell cycle prior to meiosis I but not in meoisis II.

S

DNA synthesis or replication occurs. At start of __stage, each chromosome is composed of one DNA double helix. Following replication, chromosome is identical DNA double helix molecules.

S

third phase of mitosis at the start, the two sister chromatids separate at the centromere. The daughter chromosomes appear to move towards opposite poles, but actually they are being pulled as the kinetochores spindle fibers dissasemble at the region of the kinetochores.As the daughters move toward spindle poles, the poles themselves are moving farther apart because the polar spindle fibers are sliding past one another. Motor molecules kinesin and dynein are involved in sliding processes ______ is shortest phase

anaphase

third phase of meiosis homologues of each bivalent separate and move to opposite poles, but sister chromatids don't separate.Go from 2n to n. Each chromosome still has two chromatids though.

anaphase I

The cell progresses through a series of events that bring about its destruction. The cell becomes round, causing it to loose contact with its neighbors. Nucleus fragments, plasma membrane starts developing blisters. Then white blood cell will engulf cell fragments. Enzymes called caspases are always present in cell, they bring about ____ Held in check normally by inhibitors

apoptosis

an ____ trait is carried on chromosomes, equal distribution between males and females

autosomal

Prokaryotes reproduce asexually by ______: produces two (binary) daughter cells identical to parent cell. Before divison takes place, the cell enlarges and DNA replicates. The two new chromosomes attach to a special plasma membrane site and separate by an elongation of the cell that pulls them apart. During this period, new plasma membrane and cell wall develop and grow inward to divide the cell. When cell is about twice original length, new cell wall and plasma membrane for each cell are complete.

binary fission

Prior to meiosis I, DNA replication has occurred, therefore each chromosome has two sister chromatids. During meiosis I, the homologous chromosomes come together and line up side by side, forming a SYNAPTONEMAL COMPLEX The process is called SYNAPSIS and results in a ______ (OR TETRAD): two homologous chromosomes that stay in close association during firs two phases of meiosis I.

bivalent

a cellular growth disorder that occurs when cells divide uncontrollably. Result of accumulating mutations that ultimately cause a loss of control of the cell cycle Most begin as abnormal cell grwoth that is BENIGN or not cancerous, and then grow larger When additional mutations occur and the abnormal cells fail to respond to inhibiting signals that control the cell cycle, the growth becomes MALIGNENT and it is cancerous and can spread Its cells lack differentiation They have abrnormal nuclei They do not undergo apoptosis They form tumors They undergo metastasis (getting into blood and lymph) and angiogenesis (Making new blood vessels to feed the tumor cells)

cancer

Proteins that become activated when the cell is about to advance to the next phase. These two proteins join as a cell approaches the end of a phase. Made of cyclin dependent kinase and cyclin The ____ is at its highest concentration at checkpoints

cdk-cyclin complex

when a cell enters G1 interphase, the cyclins and cdk are separate. The cell is meanwhile carrying its normal activities. However towards the end of G1, cyclin and cdk will join through phosphorylation, to form _____. When this compound peaks, checkpoint proteins will assess cell, and then it will get the green light to advance to S phase. Once cell advances to S phase, the ____ will decrease, and they will temporarily separate.

cdk-cyclin complex

_____ vs. apoptosis stay in balance, maintain homeostasis _______ increases and apoptosis decreases the number of SOMATIC (body) cells. ______ occurs your whole life.

cell division

In plant cells, you have to build a new cell wall A small flattened disk appears between the two daughter plant cells where metaphase plate was. Golgi produces vesicles which move along the microtubules to the region of the disk. As more veiscles arrive and fuse, a cell plate can be seen The ______ is newly formed plasma membrane that expands outward until it reaches old membrane and fuses with that The new membrane releases molecules that form new plant cell walls called primary cell walls, later strengthened with added cellulose fibrils. Space between cells filled with middle lamella

cell plate

Sister chromatids are constricted and attached at a region called the _______. Protein complexes called kinetochores develop on either side of _______ during cell division During nuclear division, the sister chromatids separate at ______-> give birth to two daughter chromosomes. Each has only one double helix molecule.

centromere

The ______the main microtubule-organizing center of the cell, also divides before mitosis begins. In animal cells, each _______has a pair of barrel shaped organelles called centrioles. NOT IN PLANT CELLS organize the mitotic spindle, which has many fibers composed of bundles of microtubules (made of protein tubulin monomers). The microtubules disassemble when spindle fibers begin forming (give tubulin to the spindle fibers)

centrosome

During crossing over: As the lattice breaks down, homologues temporarily held together by _____regions where nonsister chromatids are attached due to DNA strand exchange and crossing over. After exchange of genetic information between the mother and father's chromosomes, the homologues separate and are distributed to different daughter cells. The chromatids held together by a centromere are no longer identical. The daughter cells receive daughter chrmosomes with recombined alleles

chiasmata

Each double helix is called a _______

chromatid

When a euk cell isn't dividing, the DNA and proteins are located in ______ (looks like mass of thin threads) Before mitosis, _____ coils and condenses into chromosomes

chromatin

In animal cells we have a _______- an indentation of the membrane between two daughter nuclei, happens at end of anaphase. Each cell has received its share of organelles. The ________ deepens when a band of actin filaments called the CONTRACTILE RING slowly forms a circular constriction between the cells. The actin is like a drawstring.

cleavage furrow

When there are 2 dominant alleles, which are both expressed silmultaneously Ex. Roan Coats RR and C^R C^R are the same thing. RW is a mix of individual red and white hairs

codominance

an exchange of genetic material between nonsister chromatids of a bivalent (OR TETRAD) during meiosis I. At synapsis, homologues line up side by side, and a nucleoprotein lattice appears between them. The lattice holds the bivalent together in a way that the DNA of the duplicated chromosomes of each homologue pair is aligned.

crossing over

There are cell cycle checkpoints at which cell cycle either stops or continues, depending on internal signals received. There are internal signaling proteins called ____ that increase and decrease as the cell cycle continues. Specific______ must be present for cell to proceed from G1 stage to S to G2 and then M

cyclins

division of cytoplasm. Accompanies mitosis in most cells. When mitosis occurs but this doesn't, you have multinucleated cell Division of cytoplasm begins in anaphase, continues in telophase, ends when the next interphase begins. Each new cell gets its share of the organelles. Different in animal and plant cells

cytokenisis

when an end of a chromosome breaks off or when two silmultaneous breaks lead to loss of an internal segment

deletion

when you cross 2 individuals that are hybrids (heterozygous) for two traits, it is a ______ ______ (Ex. TtPp x TtPp)

dihybrid cross

(2n) number: the total number of chromosomes, exists in two sets. In humans, is 46.

diploid

Each species has characteristic chromosome number. This is the full or ____ (2n) number of chromosomes. Includes two chromosomes of each kind.

diploid

Law of ______: In every single-gene trait, one version of the trait (one allele) is dominant over the other

dominance

Mendel's first law: Law of ______: for every trait, one allele is stronger than the other

dominance

The ______ALLELE is named so because the DNA sequence that comprises that gene makes a fully functional protein

dominant

autosomal ____ disorders: affect both homozygous ____ and heterozygous Achondraplasia dwarfism Huntington's disease

dominant

trisomy 21 is

down syndrome

the presence of a chromosomal segment more than once on the same chromosome

duplication

true/false: there is crossing over/tetrad formation in mitosis

false

restores diploid number (46)

fertilization

_________is the haploid generation for plants

gameophyte

reproductive cells (eggs and sperm) have haploid number of chromosomes

gametes

sex cells. Contain half the DNA (n) of that organism's somatic cell total Therefore each has 23 chromosomes, called homologues

gametes

Due to ______, the offspring have different set of alleles from parents, increases genetic variation of the offspring.

genetic recombination

actual allelic makeup (Tt, TT, tt, etc.)

genotype

______are signaling proteins received at plasma membrane. All cells can be stimulated by these. Signals ensure that cell cycle stages go in normal sequence

growth factors

Half the diploid number is called the _____ (n) number.

haploid

To properly produce a ____ # of chromosomes in gametes, you first have to double the amount of DNA, just like in S stage. After duplication, you get two sister chromatids that make up a whole chromosome. Each has one DNA double helix molecule. Held together by the centromere. For future reference: zygotes have one chromosome from mom, one from dad (in sexual repro). So they have paired chromosomes.

haploid

half the diploid number, a single set of chromosomes. In humans, it is 23.

haploid

if an organism has two different alleles (Ff) it is

heterozygous

_______ chromosomes (homologues): In diploid body cells, the chromosomes occur in pairs called homologues Look alike, have the same length and centromere position. Have same genes, but the DNA sequence for a gene on one chromosome may code for something else (ie. Brown vs blue eyes). These are ALLELES

homologous

if an organism has two alleles that are the same (FF or ff) it is

homozygous

x-chromosome _____: in females: when only one "X" expresses traits the other is inactivated Therefore only genes from the active X are expressed (usually healthy ones!)

inactivation

when 2 alleles are paired- result in a BLENDED phenotype Ex: Red (R) and White (W) when combined make Pink (RW)

incomplete dominance

Mendel's third law: Law of _________ ______: given 2 traits, the alleles will assort independently of one another during gamete formation (EXCEPTION: linked genes, which are located very close together on chromosome)

independent assortment

the homologous chromosome pairs separate independently and randomly. Maternal or paternal homologue may be oriented toward either pole There are 2^23 (A LOT) of possible combinations.

independent assortment

Most of cell cycle time is spent in _____: the time when a cell performs its usual functions. For adult mammal cells, _________ lasts about 20 hours (90% of cell cycle). Resting stage (though not really because it has to prepare for mitosis) Three stages of _____: G1, S, and G2

interphase

Two portions of cell cycle: _____ and mitotic stage

interphase

when a segment of a chromosome is turned around 180 degrees.

inversion

XXY is

klinefelter

The term _____ refers to all reproductive events that occur from one generation to the next similar one In animals, the individual is always diploid, meiosis produces gametes, the only haploid phase of ______

life cycle

___ genes are more likely to stick together during crossing over

linked

A single gene occurs on a homologous pair of chromosomes at a particular location that is called the gene _____

locus

Fungi and plants have generations that alternate between ___ and mitosis

meiosis

____ reduces chromosome number form 2n to n. Requires two nuclear divisions that produce four haploid daughter cells, each having one of each kind of chromosome. First you replicate the chromosomes, then split the matched homologous pairs to go from 2n to n. Even though each daughter cell how has n chromosomes, each chromosome still has a sister chromatid, so you need another nuclear division The second division reduces the amount of DNA in n chromosomes to an amount appropriate for each gamete. Once DNA has been replicated and chromosomes become a pair, they may exchange genes for different mixture form the parent.

meiosis

the making of sex cells is called____. This is the formation of haploid cells. The process is specific to sexually reproducing multicellular organisms. It is reduction division. 2 rounds of division cut DNA in half.

meiosis

the type of nuclear division that reduces the chromosome number from the diploid (2n) number to the haploid (n) number

meiosis

the daughter cells contain the hapoid # of chromosomes, one chromosome form each homologous pair. However, still have duplicated sister chromatids in each chromosome. During metaphase II, the chormosomes align at metaphase plate, but do not align in homologous pairs because you only have one chromosome from each homologous pair present (other is in the other daughter cell)Sister chromatids separate, becoming daughter chromosomes that are not duplicated. Move toward poles. At end of telophase II and cytokinesis, there are four haploid cells. Each gamete contains chromosomes with mixture of mom and dad genes thanks to crossing over.

meiosis II

Second stage of mitosis the centromeres of chromosomes are now in alignment down center of the cell. An imaginary plane that passes through the center is called ______PLATE (future axis of cell division)Several nonattached spindle fibers called polar spindle fibers reach beyond ______ plate and overlap. A cell cycle checkpoint called M checkpoint delays anaphase until the kinetochores are attached properly to spindle fibers and chromosomes are properly aligned

metaphase

second phase of meiosis I Bivalents held together by chiasmata have moved toward the metaphase plate. There is fully formed spindle and alignment of the bivalents at the metaphase plate.Kinetochores are seen, but the two kinetochores of a duplicated chromosome are attached to the same kinetochore spindle fiber. Bivalents independently align themselves at metaphaswe plate. Maternal or paternal homologue of each may beoriented toward either pole of the cell. Independently oriented, alignment of one bivalent does not affect orientation of another (inependent assortment-> genetic variability)

metaphase I

During ______, a 2n nucleus divides to make daughter nuclei that are also 2n. The dividing cell= parents cell. Resulting cells = daughter cells. DNA replicates before cell division, duplicating chromosomes. This occurs during S stage of interphase! Now each chromosome has two identical double helical models. Each double helix is a chromatid, two identical chromatids are sister chromatids.

mitosis

____ is when sister chromatids are formed from one cell. It is nuclear division, cytokinesis, division of cytoplasm, etc.

mitosis

result of a _______is always 3:1 ________: crosses a single trait with organism that are hybrid (Tt x Tt)

monohybrid cross

______ (2n-1): when an individual has only one of a particular type of chromosome when they should have two. Results form nondisjunction

monosomy

when there are more than two possible alleles for one trait. Blood type is an example I^A and I^B are dominant, while i is recessive ii is O

multiple alleles

in oogenesis, you end up with __ egg and 3 polar bodies

one

The ovaries contain stem cells called oogonia that produce primary oocytes with 46 chromosomes during fetal development. They begin oogenesis, but only a few continue when a female is sexually mature The result of meiosis I is two haploid cells with 23 chromosomes each. One of these cells, termed the SECONDARY OOCYTE, receives almost all the cytoplasm. The other is a POLAR BODY that may disintegrate or divide again Secondary oocyte begins meoisis II but stops at metaphase II. Then it leaves the ovary and enters an oviduct, where a sperm may be present. If no sperm is there, it disintegrates with no meiosis completion If a sperm is there, some of its contents trigger the completion of meiosis II, and another polar body forms At completion of oogenesis, after sperm has entered, there is one egg and 2-3 polar bodies. The polar bodies are a way to "dispose" of chromosomes while retaining much of the cytoplasm within the egg Cytoplasmic molecules and organelles are needed by a developing embryo

oogenesis

it is a linear process that occurs in the ovaries. It begins in utero. After eggs form, they are frozen in metaphase I. At puberty, eggs are released once a month. Eggs do not finish meiosis unless fertilized!!!!

oogenesis

G1 checkpoint is primary check[point. The signaling protein _____stops the cycle at the G1 checkpoint if DNA is damaged. ____ will first attempt to initiate DNA repair, but rising levels of ___can bring about APOPTOSIS (programmed cell death)

p53

what you see (ex. Tall)

phenotype

in human genetics, the majority of traits are ____

polygenic

communication of several genes that result in ONE phenotype human genetics is mostly this. The phenotype has a broad range of possibilities. Ie. height, eye color, skin pigmentation, etc.

polygenic inheritance

occurs during meiosis I when both members of a homologous pair go into the same daughter cell. You get NO normal gametes (so worse than secondary nondisjunction, more deleterious)

primary nondisjunction

(late prophase). Preparations for sister chromatid separation are evident. Kinetochores appear on each side of the centromere, and these attach sister chromatids to the kinetochore spindle fibers. These fibers extend from the poles of the chromosomes. The kinetochore fibers attach to sister chromatids from opposite poles of the spindle, the chromosomes are pulled into alignment. Even though chromosomes are attached to the spindle fibers in prometaphase, they are not YET aligned

prometaphase

First stage of Mitosis Chromatin has condensed and chromosomes are visible. Parental chromosomes have ALREADY duplicated and formed sister chromatids held together at centromere!!! Nucleolus disappears and nuclear envelope fragments. The spindle begins to assemble as two centrosomes migrate away from each other. In animal cells, an array of microtubules radiates toward the plasma membrane from the centrosomes. These structures are called ASTERS. Brace the centrioles during later stages.

prophase

first phase of meiosis spindle forms, centrosomes migrate to opposite end of cell. Nuclear envelope fragments, nucelolus disappears.Homologous chromosomes have ALREADY REPLICATED in S phase, so consist of 2 sister chromatids. They undergo synapsis to form bivalents. Crossing over may occur Throughout _______, homologous chromosomes have been condensing so they now look like compacted metaphase chromosomes

prophase I

code for proteins that promote the cell cycle and prevent apoptosis. Like the gas pedal of car because they can cause cell cycle to speed up

proto-oncogenes

Autosomal ______disorders: when the affected individual is homozygous ______ Ex. Cystic fibrosis Tay Sachs Sickle cell anemia

recessive

The ______- ALLELE contains a slightly different DNA sequence and produces a protein with little or no function

recessive

DNA replication occurs only once during meiosis. NO ____BETWEEN MEIOSIS I AND MEIOSIS II because chromosomes are already duplicated.

replication

two identical chromatids are called _________. Remain attached until mitosis

sister chromatids

Testes have stem cells called spermatogonia. Primary spermatocytes with 46 chromosomes undergo meiosis I to form two secondary spermatocyctes with 23 duplicated chromosomes each Secondary spermatocytes undergo meiosis II to produce four spermatids with 23 daughter chromosomes Spermatids then differentiate into viable sperm (spermatozoa).

spermatogenesis

_________ is the diploid generation for plants Majority of a plant species are usually diploid, with haploid generation beings short lived. In plants, algae, and fungi, the haploid phase of the life cycle produces gamete nuclei without the need for meiosis because it occurred earlier.

sporophyte

In Meiosis: After ____, homologous pairs align at metaphase plate, and then members of each pair separate. Only one duplicated chromosome from each homologous pair reaches a daughter nucleus, so we go from n to 2n. Each daughter nucleus must have a member from each pair of homologous chromosomes because then we have a copy of each KIND of chromosome in the daughter nuclei. Ex. Daughter needs one short and one long. So can have a short form mother and a long from father, or long from mother and short from father.

synapsis

Prior to meiosis I, DNA replication has occurred, therefore each chromosome has two sister chromatids. During meiosis I, the homologous chromosomes come together and line up side by side, forming a SYNAPTONEMAL COMPLEX The process is called ____ and results in a BIVALENT (or tetrad): two homologous chromosomes that stay in close association during firs two phases of meiosis I.

synapsis

the spindle dissapears as new nuclear envelopes form around daughters. Each daughter nucleus contains same number of chromosome as parent. Remnants of polar spindle fibers still visible. Chromosomes become chromatin, new nucleolus formed.Division of cytoplasm requires cytokinesis.

telophase

fourth phase of meiosis completion of this phase not necessary during meiosis. The spindle disconnects, but new nuclear envelopes don't need to form because we go on to Meiosis II. May or may not be cytokinesis.

telophase I

an orderly set of stages that take place between the time a eukaryotic cell divides and the time the resulting daughter cells also divide.

the cell cycle

the movement of a chromosome segment from one chromosome to another, nonhomologous chromosome. Can be BALANCED, meaning that there is a reciprocal swap of one piece of the chromosome for the other. Can also be UNBALANCED, with extra material from one chromosome and missing material from another

translocation

(2n+1): when an individual has three of a particular type of chromosome when they should have two/ Results form nondisjunction

trisomy

XXX is

trisomy x

code for proteins that inhibit the cell cycle and promote apoptosis. Like the brakes of a car.

tumor suppressor genes

XO is ___ syndrome

turners