Module 4, Cell division Flashcards

Question

G1, S, G2

Answer 1

Growth 1 (G1) Phase: acquisition of nutrients and growth 2. Synthesis (S) Phase: DNA synthesis, every chromosome is replicated 3. Gap 2 or Growth 2 Phase (G2): completion of cell growth and preparation for division

Answer 2

Mitosis – Involves the division of the nucleus Content of nucleus divides and separate into two complete sets. Cytokinesis – Cytoplasm and organelles divide into two separate cells (daughter cells)

Answer 3

Before DNA replication (G1 phase) Each chromosome consists of one DNA double helix The chromosome is unduplicated It is a single chromatid Not yet paired with a sister chromatid 👉 In short: 1 chromosome = 1 DNA double helix After DNA replication (S phase, before mitosis/meiosis) Each chromosome is now duplicated It consists of two identical sister chromatids The sister chromatids are: Each made of one DNA double helix Held together at the centromere Still considered one chromosome until separation 👉 In short: 1 chromosome = 2 identical DNA double helices (sister chromatids) After sister chromatids separate (during anaphase) Sister chromatids separate Each chromatid becomes an independent daughter chromosome Each daughter chromosome has: One DNA double helix Identical genetic information 👉 In short: Separated sister chromatids = independent chromosomes

Answer 4

Mitotic cell division takes place in all eukaryotic organisms * It is the mechanism of asexual reproduction * Mitotic cell division followed by differentiation of the daughter cells allows a fertilized egg to grow into an adult with perhaps trillions of specialized cells * It allows organisms to maintain, repair, and even regenerate body parts

Answer 5

mitosis: It is the mechanism whereby stem cells reproduce.

Answer 6

Prophase Metaphase Anaphase Telophase

Answer 7

Chromatin condensed into chromosomes; * Nuclear membrane breaks down and chromosomes releases into cytoplasm; * Nucleolus disappears; * Centriole move to opposite poles; * Spindle apparatus form between them “Centrioles move to opposite poles” Centrioles are small structures that help organize cell division During prophase, the two centrioles move away from each other They go to opposite ends (poles) of the cell 👉 This sets up the “left side” and “right side” of the cell so things divide evenly. “Spindle apparatus forms between them” As the centrioles move apart, spindle fibers (thin protein threads) form These fibers stretch from one centriole to the other The spindle fibers will later attach to chromosomes 👉 Their job is to pull chromosomes apart during division.

Answer 8

Chromosomes is at the equator of the cell; * Centrioles are at each poles of the cell.

Answer 9

Centromere split and chromatids split from each other; * Spindle fibers shorten and chromatids move to opposite poles; * At the end, one diploid set of chromosomes are at each end of the cell.

Answer 10

Begins when chromatids reach opposite poles of the cell; * Chromatids unwind into longer strands of chromatin; * Spindle fibers break down; * Nuclear membrane forms around new set of chromosomes * Nucleolus forms within each new nucleus.

Answer 11

Late Interphase Duplicated chromosomes are in the relaxed uncondensed state; duplicated centrioles remain clustered.

Answer 12

Early Prophase Chromosomes condense and shorten; spindle microtubules begin to form between separating centriole pairs

Answer 13

Late Prophase (also called Prometaphase) The nucleolus disappears; the nuclear envelope breaks down ALLOW some spindle microtubules attach to the kinetochore (blue) located at the centromere of each sister chromatid which will pull it apart later

Answer 14

Kinetochore microtubules line up the chromosomes at the cell’s equator.

Answer 15

Anaphase Sister chromatids separate and move to opposite poles of the cell; polar microtubules push the poles apart. Telophase One set of chromosomes reaches each pole and begins to decondense; nuclear envelopes start to form; nucleoli begin to reappear; spindle microtubules begin to disappear; microfilaments form rings around the equator. Cytokinesis The ring of microfilaments contracts, dividing the cell in two; each daughter cell receives one nucleus and about half of the cytoplasm. Interphase of daughter cells Spindles disappear, intact nuclear envelopes form, and the chromosomes extend completely.

Answer 16

Cytoplasm and organelle divide equally;  Indentation forms in cell membrane;  Indentation deepens until cell is pinched into two daughter cells;  Daughter cells are in G1 of Interphase. Chromosome number is maintained in mitosis because sister chromatids separate and are evenly distributed to opposite poles before cytokinesis, so each daughter cell receives a complete diploid set of chromosomes. Mitosis separates sister chromatids; meiosis I separates homologous chromosome pairs.

Answer 17

Comparison of Cytokinesis in Plant and Animal Cells Plant Cells Cytokinesis occurs by cell plate formation Vesicles from the Golgi apparatus gather at the center These vesicles fuse to form a cell plate The cell plate grows outward and becomes the new cell wall No cleavage furrow forms Animal Cells Cytokinesis occurs by cleavage A cleavage furrow forms at the cell’s equator The plasma membrane pinches inward Contractile ring of actin and myosin helps separate the cells No cell wall is formed

Answer 18

Important for growth, repair and maintenance of tissues; However, division must be regulated: * Regulated by regulatory signals that ‘start’ and ‘stop’ signals; * Rapid uncontrolled cell division causes Cancer

Answer 19

Reduction Division - produces daughter cells with half the no. of chromosomes as parent cells; 2. Recombination – daughter cells produced has diff. combination of genes, hence differ from each other and parent Purpose of Meiosis I – “HALF & MIX” Applied idea: Meiosis I is all about reducing chromosome number and creating genetic diversity. Reduces chromosome number: Homologous chromosomes (mom + dad) separate Results in haploid cells (n), so gametes won’t double chromosome number at fertilization Mixes genetic material: Crossing over swaps DNA between homologous chromosomes Random alignment during metaphase I → independent assortment Creates unique combinations for offspring Example in real life: In humans, meiosis I ensures that sperm or egg cells each have 23 chromosomes, and each gamete is genetically unique. Purpose of Meiosis II – “SPLIT & FINALIZE” Applied idea: Meiosis II is all about separating sister chromatids to make functional gametes. Separates sister chromatids: Each haploid cell from meiosis I divides again Produces four haploid gametes in total Finalizes genetic content: Each gamete has one copy of each chromosome Ensures correct chromosome number when fertilization occurs Example in real life: In females: meiosis II produces one functional ovum In males: meiosis II produces four functional sperm cells

Answer 20

During sexual reproduction, gamete from male fuses with gamete from female to form zygote; * Zygote has genetic info. from both parents (half from mother and half from father); * Process that produces haploid gametes is Meiosis

Answer 21

2n--n--2n 2n--n--2n both meet at the 2nn, 2n first = diploid parental cells, n=haploid gametes, become 2n via fertilization

Answer 22

Prophase, Metaphase, Anaphase and Telophase  Involves two (2) complete cycles of the above phases

Answer 23

MeiosIs I - separates homologous chromosomes, to produce haploid daughter nuclei. Meiosis II - Meiosis II separates sister chromatids into four daughter nuclei

Answer 24

Prophase 1 - Homologous chromosomes pair up and exchange DNA (synapsis); - Crossing Over occurs; - During synapsis: * Homologous chromosomes pair up; * Each chromosomes consists of two chromatids * Hence, pair of homologous chromosomes consists of four chromatids (tetrad).

Answer 25

Exchange of sections of chromatids between maternal and paternal homologues; — Enzymes cut through DNA of paired homologues and graft cut ends back together, switching maternal and paternal ends; — Leave crosses or chiasmata (singular, chiasma), where maternal and paternal chromosomes have exchanged parts;  Result in chromosomes containing genes of maternal and paternal origin.

Answer 26

Metaphase 1 - Paired homologous chromosomes line up at the equator of the cell; - Spindle fiber attaches to centromere of each homologous chromosomes; - Guide each tetrad to the equator of the cell

Answer 27

Duplicated homologous chromosomes are pulled perpendicular to the spindle. A daughter cell receive any combination of maternal and paternal homologues  This random combining of maternal and paternal homologues (and, therefore, alleles) is called independent assortment

Answer 28

Genetic recombination and independent assortment are responsible for genetic diversity of the haploid cells produced by meiosis.

Answer 29

Anaphase 1 - Spindle fibers shorten: - Whole duplicated chromosomes of each homologous pair separate from each other; - One duplicated chromosome of each homologous pair moves to each pole, pulled by microtubules - Sister chromatids still held by centromere; - Single chromosome (2 sister chromatids) from each homologous pair move to opposite pole of ce

Answer 30

Homologous chromosomes reach opposite poles ↓ Two haploid clusters of duplicated chromosomes form ↓ Homologous chromosomes begin to uncoil ↓ Spindle fibers disappear ↓ Nuclear membrane forms around each chromosome cluster ↓ Cytoplasm divides (cytokinesis) ↓ Two haploid cells are formed (each cell has one set of duplicated chromosomes)

Answer 31

Telophase I is usually followed immediately by meiosis II, with little or no intervening interphase

Answer 32

Occurs during Metaphase I;  Chromosomes arranged in homologous pairs along equator;  Maternal chromosomes faces one pole of the cell and paternal chromosomes faces the other pole;  Result in gametes with diff. combinations of maternal and paternal chromosomes

Answer 33

Occurs during Prophase I;  Homologous chromosomes pair upside by side;  Non-sister chromatids may exchange pieces of chromosomes (crossing over);  Result in chromosomes containing genes of maternal and paternal origin

Answer 34

Cell goes through prophase II, metaphase II, anaphase II, and telophase II as in Mitosis;

Answer 35

Meiosis II separates sister chromatids into four daughter nuclei; o Daughter cells are haploid and contain single replicated chromosome.

Answer 36

Prophase II o If decondensed, chromosomes recondense o Spindle microtubules re-form and capture duplicated chromosomes to pull them to opposite sides of the cell

Answer 37

Metaphase II o Duplicated chromosomes line up singly, perpendicular to the spindle

Answer 38

Anaphase II o Chromatids separate and move to opposite poles

Answer 39

1️⃣ Prophase I (the long one) This is the big event stage. What happens: Chromosomes condense (you can see them) Homologous chromosomes pair up (one from mom, one from dad) → called synapsis They form tetrads (4 chromatids total) Crossing over happens → chromatids swap pieces = genetic diversity Nuclear membrane breaks down Spindle fibers form 🧠 Key idea: DNA is mixed and matched here 2️⃣ Metaphase I What happens: Paired homologous chromosomes line up at the middle of the cell Alignment is random (independent assortment) 🧠 Key idea: which parent’s chromosome goes where is random 3️⃣ Anaphase I What happens: Homologous chromosomes separate One whole chromosome (still 2 sister chromatids) goes to each side Sister chromatids stay together 🧠 Key idea: chromosome number is reduced 4️⃣ Telophase I + Cytokinesis What happens: Chromosomes reach opposite poles Cell divides into two cells Each cell is haploid (n) Chromosomes are still duplicated (sister chromatids attached) 🧠 Key idea: two genetically different haploid cells are made ⭐ One-line memory trick Meiosis I separates homologous chromosomes (Meiosis II separates sister chromatids)

Answer 40

Cytokinesis occurs, nuclear membranes re-form, and chromosomes decondense o The two nuclear divisions of meiosis produce four haploid cells from a single diploid cell.

Answer 41

Cytokinesis results in four haploid cells, each containing one member of each pair of homologous chromosomes (shown here in the condensed state).

Answer 42

meisosi I, prophase I: pairing of homologous chromosomes mitosis, prophase: no pairing of chromosomes metaphase I, meiosis: homologous duplicated chromosomes at metaphase plate Metaphase, Mitosis: duplicated chromosomes at metaphase plate Anaphase I, Meiosis: homologous chromosomes separate Anaphase: sister chromatids separate, becoming daughter chromosomes that move to the poles Telophase I, Meiosis: two haploid daughter cells telophase, cytokinesis, mitosis: two daughter cells, identical to the parental cell

Answer 43

haploid=n diploid=2n adults=2n meotic cell division in ovaries/testes: egg (n) and sperm (n/0 fusion of gametes= zygote (2n) embryo= 2n baby=2n

Answer 44

Process in which chromosomes or sister chromatids do not separate. Occurs in Anaphase I and Anaphase II Anaphase I - homologous chromosome pairs do not separate to opposite poles, BUT one pair pulled towards same pole; Anaphase II - sister chromatids do not separate to opposite poles BUT both sister chromatids pulled toward same pole.

Answer 45

Produces gametes with too few or too many chromosomes. Effects of Nondisjunction 1. Monosomy - one chromosome is lost. E. g. Turner Syndrome (X chromosome is missing). 2. Trisomy – one chromosome is gained. E. g. Down syndrome (extra chromosome # 21).

Answer 46

Normal XX females have one X chromosome inactive. * A zygote with one X chromosome (Turner syndrome) can survive. – All extra X chromosomes become deactivated. * Poly-X females and XXY males are seen fairly frequently. – Extra Y chromosomes are also tolerated. * Jacobs syndrome (XYY) is due to nondisjunction during meiosis II of spermatogenesis.

Answer 47

can be either male or female patau: trisomy 13, chromosome 47 edwards: trisomy 18. chromosome 47

Answer 48

klinefelter: male, XXY or XXXY, chromosome 47 or 48 turner: female only, chromolsomes X, chromosome 45

Answer 49

malw only, chromosomes=XYY, chromosome 47

Answer 50

down: mental retardation, abnormal pattern of palm creases, slanted eyes, flattened face, short, early death edward: mental and physical retardation, facial abnormalitiies, extreme muscle tone, early death patau: mental and physical retardation, wide variety of defects in organs, large triangular nose, early death

Answer 51

short stature, webbed neck, sexually undeveloped

Answer 52

sexual immaturity, breast swelling in males XXY

Answer 53

Down Syndrome – trisomy 21 — Most common autosomal trisomy among humans — Easily recognized physical features — Chances of having a Down syndrome child increase rapidly with age, starting at about age 40 — Some symptoms may be due to expression of Gart gene  Mild to severe mental impairmen

Answer 54

An abnormal sex chromosome number is caused by inheriting too many or too few X or Y chromosomes.  Nondisjunction during oogenesis or spermatogenesis results in gametes with too few or too many X and Y chromosomes.  Fertilization of the gametes can lead to various syndromes.

Answer 55

Presence of Y chromosome, not the number of X, determines maleness. — SRY gene produces a hormone, testis- determining factor — Plays a key role in male genital development

Answer 56

Females have one X chromosome.  Usually are short with malformed features, such as webbed neck, high palate, and small jaw  Many have congenital heart and kidney defects  Most have ovarian failure and do not undergo puberty or menstruate without hormone therapy.

Answer 57

A male with 2 X and one Y chromosome  Subtle symptoms; usually not diagnosed until age 15  Usually experience speech and language delays  Require assisted reproduction to father children

Answer 58

Poly-X females have more than two X chromosomes. — They are usually taller, with no other distinctive phenotypes. — Some have delayed motor and language development. — Some may have menstrual difficulties, but most do so regularly and are fertile. — Their children usually have normal karyotypes.

Answer 59

XYY males result from nondisjunction during spermatogenesis. — Males are usually taller, suffer from persistent acne, and tend to have speech and reading abnormalities. — There is typically no behavioral differences between an XY and XYY male.

Answer 60

Gametes are Sperm and Egg. Spermatogenesis - Production of sperm Oogenesis – Production of egg. Both processes involves Meiosis to produce haploid gametes.

Answer 61

Spermatogonia divide by mitosis to form 2 daughter cells:  One daughter cell replenish spermatogonia population;  Next daughter cell develops into Primary Spermtocyte.  Primary spermatocyte undergo meiosis I to form two Secondary spermatocytes:  Secondary spermatocytes undergo meiosis II to form four spermatids;  Spermatids mature into sperm.

Answer 62

mitossis, meiosis I, meiosis II, differentiation GERM CELLS CAN DO MITOSIS, SEX CELLS DONT

Answer 63

Starts with a diploid cell (Oogonium);  Each oogonium goes through mitosis to form 2 primary oocytes:  1° oocyte remain until puberty.  Every month after puberty, one 1° oocyte undergo meiosis I:  Involves unequal division of cytoplasm (asymmetrical cytokinesis)  Form two daughter cells: Secondary oocyte (larger cytoplasm) and first polar body.  First polar body non-functional and disintegrate.

Answer 64

Secondary oocyte undergo meiosis II:  Cytoplasm is unequally divided to form two daughter cells;  Cell with most cytoplasm, contain nutrients and becomes an egg/ovum;  Other cell, second polar body disintegrate.

Answer 65

Oogonium (2n) │ Mitosis ▼ Primary oocyte (2n) │ Meiosis I (asymmetric division) ▼ Secondary oocyte (n) + First polar body (n) │ Meiosis II (only if fertilization occurs) ▼ Ovum / Egg (n) + Second polar body (n) 🧠 Key things to remember (exam gold): Only ONE functional egg is produced Polar bodies get rid of extra chromosomes Oogenesis results in 1 ovum + 3 polar bodies Meiosis II only finishes if fertilization happens

Answer 66

Primary oocytes begin Meiosis I before birth; - BUT remains in Prophase I until puberty; - At puberty, hormone signal 1°oocyte to resume Meiosis I; - Meiosis I is completed; - 2° oocyte released and travel down Fallopian tube and remains in Metaphase II until fertilization

Answer 67

If fertilization does not occur, 2° oocyte will NOT complete Meiosis II; - If fertilization occurs, 2° oocyte complete Meiotic II: - Produces an ovum or egg cell and a polar body; - Haploid egg fuses with haploid sperm to form a zygote

Answer 68

Organs called gonads produce haploid sperm or eggs through meiotic cell division;  Female gonad, called the ovary, produces eggs;  Male gonad, called testis (plural, testes), produces, motile sperm.  Sperm and egg fuse (fertilization) to form a zygote >>>>mitotic cell divisions to produce offspring;  Offspring is not genetically identical;  Genetic variability allow offspring to survive (exploit new habitats, acquire food and avoid predation)

Answer 69

Asexual Reproduction  Single animal produces offspring, through repeated mitotic cell division in some part of its body;  offspring are genetically identical to the parent;  Org. reproduces without mating;  Efficient in effort: no need to search for mates, court members of opposite sex, or battle rivals, no wasted gametes and offspring have all the genes of their parent;  Several common methods of asexual reproduction in the animal kingdom are: Budding, Fission and Parthenogenesis.

Answer 70

Binary Fission; 2. Conjugation; 3. Budding; 4. Vegetative Reproduction; 5. Fragmentation; 6. Parthenogenesis and 7. Spore Formation

Answer 71

Binary Fission - A method of asexual reproduction that involves the splitting of a parent cell into two daughter cells. 2. Conjugation – transfer of genetic material from one cell to another through a bridge called a Pilus.

Answer 72

Asexual Reproduction - Budding Miniature version of parents grow out from parent’s body to form a complete new individual; Cells from parent undergo mitosis; Differentiate into specific types of structures before the new individual breaks away from the parent; Continues throughout an animal’s lifetime.

Answer 73

Fragmentation  Creation of new plant from a fragment/portion of parent plant, E. g Potatoes

Answer 74

Eggs develop into viable offspring without fertilization;  In some species, offspring are haploid; E. g. Honeybees, queen bee lays both fertilized and unfertilized eggs:  Fertilized eggs develop into male worker bees;  Unfertilized eggs develop into male drones.

Answer 75

Spores – structure that contain genetic material and cytoplasm surrounded by a wall: * Small and dispersed by wind or water; * Walls protect spore content until favorable cond'tn; * Wall opens and org. begin to develop.  Spores may be haploid or diploid;  Some spore may be produced by meiosis:  Result in alternation of generations

Answer 76

Life cycle involves a Sporophyte (diploid) generation and a Gametophyte (haploid) generation: * Sporophyte generation produces haploid spores by meiosis; * Spores develop and grows into a plant body, Gametophyte; * Gametophyte produces male and female gametes; * Gametes fuse at fertilization to form another sporophyte; * Cycle continues. * Found only in plants, except Phylum Cnidaria (jelly fish, sea anemone

Answer 77

Gametophyte is Leafy green mat;  Stalks (Sporophyte) grows on mat and releases spores from its cap;  Spores fall to ground and develop into leafy Gametophyte;  Gametophyte develop structures that produces sperm and eggs;  Sperm swim to the eggs and fertilize them;  Fertilized eggs developed into new stalk  Cycle continues

Answer 78

Sporophyte stage (2n) – the tree itself The conifer tree is the diploid sporophyte. It produces two types of cones: Male cones (smaller) → produce pollen Female cones (larger) → produce ovules Gametophyte formation (n) Female cones: Inside each scale, meiosis occurs → haploid spores are produced. These spores develop into female gametophytes, but stay inside the ovule (protected). Male cones: Inside each scale, meiosis produces haploid spores. These develop into male gametophytes (pollen grains). Pollen is released into the air for dispersal. Fertilization Pollen grains reach the female gametophyte. Sperm (from pollen) fertilizes the egg (in female gametophyte) → forms zygote (2n). Seed formation The zygote grows into an embryo inside the seed. Seed can eventually grow into a new sporophyte tree.

Answer 79

Advantages of Sexual Reproduction Advantages of Asexual Reproduction Offspring adapt to changing environment Proceeds quickly and do not need a second parent Reduced competition among siblings as they are genetically diverse Requires less energy Damaged chromosomes can be replaced or repaired Greater no. of offspring

Answer 80

Meiosis I – “HALF & MIX” Outcome: Chromosome number is cut in half Produces 2 haploid cells Chromosomes are still duplicated Cells are genetically different 🧠 Acronym: HALF Halve chromosome number Altered genes (crossing over) Leaves sister chromatids together Forms 2 cells Meiosis II – “SPLIT” Outcome: Chromosome number stays the same Produces 4 haploid cells total Sister chromatids separate Cells are genetically different 🧠 Acronym: SPLIT Sister chromatids separate Produces 4 total cells Leaves chromosome number the same Identical? ❌ (still different) Two divisions total (including meiosis I)

Answer 81

Each cycle, one secondary oocyte (n) is released from the ovary during ovulation. This cell has completed meiosis I. It is arrested at metaphase II of meiosis II. This is what is usually called the “egg” that is ovulated — technically, it’s not yet a mature ovum.

Answer 82

by replicating DNA in the S interphase first, then seperating sister chromatids during anaphase

Answer 83

by spewrating homologous chromsomes = reduces the chromosome count, , nuclear membranes reform to produce two haploid cells

Answer 84

Meiosis II separates sister chromatids of the two haploid cells from meiosis I, producing four haploid daughter cells, each with one copy of every chromosome.

Answer 85

chromomsomes= throughouyt the cell cycle chromatids: exist only afeter the s phase of reeplication

Answer 86

Golgi apparatus: Modifies, sorts, and packages proteins and lipids for transport to their destinations in or out of the cell. Endoplasmic reticulum: Synthesizes proteins (rough ER) and lipids (smooth ER) and helps transport them within the cell. Lysosome: Breaks down waste materials, damaged organelles, and macromolecules using digestive enzymes. Centriole: Organizes microtubules and helps form the spindle fibers during cell division.

Answer 87

plants, fungi, animals

Answer 88

Nuclear envelope Nucleolus Chromatin

Answer 89

1. DNA double helix 2. DNA winds around histine proteins 3. has coiled DNA and hisdtoine beads 4. loops attach to ptrotein scaffold: this typically occurs in cells that are not dividing 5. results in a fully folded chromosome

Answer 90

crossing over independent assortment

Answer 91

Vegetative reproduction, or propagation, is a form of asexual plant reproduction where new, genetically identical plants (clones) grow from a parent plant's vegetative parts like roots, stems, or leaves, rather than seeds or spores, using natural methods (rhizomes, tubers, bulbs) or artificial techniques (cutting, grafting, layering) for rapid, uniform multiplication

Answer 92

Life cycle involves a Sporophyte (diploid) generation and a Gametophyte (haploid) generation: * Sporophyte generation produces haploid spores by meiosis; * Spores develop and grows into a plant body, Gametophyte; * Gametophyte produces male and female gametes; * Gametes fuse at fertilization to form another sporophyte; * Cycle continues. * Found only in plants, except Phylum Cnidaria (jelly fish, sea anemone

Answer 93

Gametophyte is Leafy green mat;  Stalks (Sporophyte) grows on mat and releases spores from its cap;  Spores fall to ground and develop into leafy Gametophyte;  Gametophyte develop structures that produces sperm and eggs;  Sperm swim to the eggs and fertilize them;  Fertilized eggs developed into new stalk

Answer 94

22 autrosomes, 1 sex chromosome pair

Answer 95

Location: Spindle fibers extend between spindle poles (centrosomes) and chromosomes. Kinetochores are located on the centromere of each sister chromatid. Function: Spindle fibers act as "ropes" that guide and move chromosomes. Kinetochores act as the attachment site for these ropes, facilitating binding and tension monitoring.

Answer 96

respiratory system

Answer 97

1st division= 2 cells 2nd dvision=4 cells 3rd division= 8 cells only number of cells incrfeases, not mass MORULA=16 CELLS

Answer 98

trophoblasts =become chorion inner mass cells= embryo

Answer 99

male gametophyte, which prodcuces male gamete spore, gametophyte, GAMETES, ZYGOTE, sphorophyte fertilization

Answer 100

type of cell division gone wrong in cancer

Answer 101

transport from one place to another, structure of cell

Answer 102

double membrane nucelaus houses DNA, carries blueprints for making proteins

Answer 103

protein processing occurs here; cells network of internal membranes rough ER: covered in ribosomes, makes it rough no endomembrane system in prokaryotes

Answer 104

live in almost any temp/bacteria

Answer 105

went onto to produce protocell, which then produced cyanobacteria, archea, then eukarya

Answer 106

plants, animals and protists

Answer 107

= 46 total chromosomes

Answer 108

how each strand runs with one another

Answer 109

first cell, daughter cells are offspring

Answer 110

occurs in all living organisms= naisl grow back bc of mitosis

Answer 111

has cytokinesis, but doesnt pinch, forms the cell plate NO CENTRIOLES IN PLANTS BUT STILL HAS SPINDLE FIBERS

Answer 112

control cell divison

Answer 113

✅ Increase in size (grow and make proteins/organelles) ✅ Differentiate (specialize in structure and function, depending on the cell type) ✅ Respond to internal and external signals to decide whether to: Move forward to the S phase (DNA replication), or Exit the cycle into G₀ (a resting/non-dividing state)

Answer 114

G1 → S → G2 → M

Answer 115

So the G1 → S checkpoint makes sure: The cell is large enough There are enough nutrients/resources The DNA is undamaged Conditions are favorable for division

Answer 116

DNA was copied correctly (no damage or mutations) The cell is large enough and has enough organelles and proteins for division The cell is ready to enter mitosis safely

Answer 117

all chromosomes are properly aligned at the metaphase plate Spindle fibers (microtubules) are correctly attached to the kinetochores of each chromosome Sister chromatids are ready to separate without errors

Answer 118

1. Actin filaments form a ring around the cell’s equator. 2. The contractile ring contracts, pinching in the cell’s “cleavage furrow.” 3. he “cleavage furrow” completely pinches off, forming two daughter cells

Answer 119

Carbohydrate-filled vesicles bud off the Golgi apparatus and move to the center of the cell. The vesicles fuse to form a new cell plate and plasma membrane between the two daughter cells. Complete separation of the two daughter cells.

Answer 120

Key point: Meiosis is part of the cell cycle for germ cells, and it starts after DNA replication in S phase,

Answer 121

The terminal ends or "tips" of a chromosome are called telomeres.

Answer 122

mitosis: body functions meiosis: sesxual functions

Answer 123

interphase: still has nucleaulos early prophase: no nucleaulus, chromatin starting to condense late propahse: looks like a hybrid between anaphase/metapahase

Answer 124

mitosis prophase early: no condensed chromosomes meiosis prophase: homologous chromosomes already formed meiosis 2 prophase: sister chromatids aslready fromed

Module 4, Cell division Flashcards

(151 cards)