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124 Cards in this Set
- Front
- Back
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What is called when you split up the DNA?
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Mitosis
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Why do cells divide rather than keep growing bigger and bigger?
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1) The cell has more trouble moving enough nutrients and wastes across the cell membrane (remember big city with a 1 lane road: less volume per surface area) 2) The larger the cell becomes, the more demands the cell places on its DNA
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What is cell division? What steps does it follow?
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When a growing cell divides forming 2 daughter cells. Made up of mitosis and cytokinesis
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Cytokinesis
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last step of cell division where they split up the cytoplasm and the cells pinch off and become two daughter cells
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Cytoplasm
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thick liquid in the cell that everything in the cell floats in
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What must happen before cell division that ensures the daughter cells will have DNA? And where in the cell cycle does it happen.
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The DNA must duplicate
This happens in the S part of Interphase |
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Draw the cell cycle and label the parts
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Really - don't skip this step
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4 parts of mitosis
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PMAT: Prophase, Metaphase, Anaphase, Telophase
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how many copies of chromosome 21 does a gamete (sperm or egg) have
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1 (haploid only one copy of each chromosome)
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how many copies of chromosome 21 does a body cell have
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2 (we are diploid)
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does asuexual reproduction use mitosis or meiosis
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mitosis (if making clones) meiosis if self pollinating like a plant
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does cloning happen naturally in nature
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Yes (mitotic asexual reproduction
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What is a chromosome and what is it made out of
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Tightly coiled strand of DNA wrapped around proteins called histones
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Why are chromosomes only visible during certain times in the cell cycle?
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They are very condensed during mitosis, and unraveled during the rest of the cell cycle
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Centromere
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Middle of chromosome X during mitosis and meiosis where the spindle fibers attach
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What is a chromatid
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When the DNA is already doubled and condensced and it looks like an X it is one side ( >) When they get pulled apart they are no longer chromatids they are 2 separate chromosomes
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How many chromosomes do humans have?
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46
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What is the cell cycle?
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A series of events that cells go through
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What are the phases of the cell cycle?
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Interphase is a period of growth and replication in between division it is comprised of G1, S and G2 phase
G1 phase: cell grows & makes proteins & organelles S phase: chromosome (DNA) replication (stands for synthesis) G2 phases: preparation for cell div |
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What happens during S phase of the cell cycle
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Duplicate DNA
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What phase of the cell cycle is DNA replicated
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The S phase of interphase
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What part of the cell cycle describes the everyday general life of a cell
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interphase
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What part of the cell cycle describes when cells are splitting in half to become 2 cells
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Cell division, which is made up of mitosis and cytokinesis.
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What is it called when you take 2 haploid cells and stick them together to make a diploid cell
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Fertilization - this is when the egg and sperm hook up.
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How many copies of chromosome 21 does a sperm have
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One - sperm are diploid
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how many copies of chromosome 21 does a body cell have
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2 - body cells are diploid
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How many copies of chromosome 21 does somebody with Downs syndrome have
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3 - Downs syndrome is called trisomy 21. It is a disease caused by having an extra copy of chromosome 21 caused by nondisjunction during meiosis.
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What info is in the nucleus at the start of meiosis 1
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There are 2 doubled copies of each chromososme. Which means there are 2 Xs for each chromosome. This means that there are 4 copies of information (remember when a chromosome looks like an X it is 2 copies stuck together)
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What chromosome has the genes for most sex linked diseases?
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The X chromosome. They Y chromosome is very small and doesn’t have many genes on it.
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Why do men get sex linked recessive diseases more often than women.
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They only have 1 copy of the X chromosome (from mom) so if they get the recessive disease chromosome they will express the disease.
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What has to happen for you to have symptoms for a recessive disease
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Every copy of a chromosome that carries the gene has to have a disease copy. If you have 2 chromosomes and one has a good copy you don't get the disease.
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What is polyploidy
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when you have more than 2 copies of each chomosome. Humans have 2 copies of each chromosome but some plants have 3 or 4 or even more.
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What are genes
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The information to make a protein
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What do genes code for
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proteins
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What is an allele
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A different version of a gene. If a gene is for hair color, one allele could be for black, another allele (or version of that gene) could be for red, or white, or whatever
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What do you call an animal with 2 of the same copies of a gene
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homozygous for that gene
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What do you call an animal with 2 different copies of a gene
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heterozygous
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What is the difference between genotype and phenotype
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Genotype is what you get (genetic makeup) Phenotype is what you look like
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What does dihybrid mean
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2 genes with both versions of alles. For example if you L=long, l-short, B-black, b-white. If you are a dihybrid you have both genes one for length and one for color and you have both copies of each. In this case its genes would be BbLl.
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Give an example of a trait controlled by multiple alleles.
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Hair color
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How do you know if a trait is polygenic
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a polygenic trait has a range of possibilities. Hair color is not either black or red or blond, but it can be anywhere on a spectrum of colors
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How many copies of each chromosome does a human hair cell have
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2 - humans are diploid which means that any cell that is not egg or sperm has 2 copies of each chromosome
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When do cells have chromatids
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Only during meisis or mitosis when the chromosomes look like an X. When they are pulled apart and look like a > they are called chromosomes
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Explain the number of cells and their DNA makeup at the end of meiosis I / beginning of meiosis II
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First cell is now 2 cells with only one copy of each chromosome. That chromosome is made up of sister chromatida, looks like an X and is ready to to be split into individual chromosomes
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When during meiosis do things become haploid?
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At the end of meiosis 1
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what is the point of meiosis 1
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to make the cell haploid
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What do you know about a chromosome that looks like an X
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Any chromosome that looks like an X is doubled and is going to be split into 2 halves (If you see Xs you know the cell is going through either meiosis or mitosis)
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By looking at a cell how can you tell if it is going to or has just divided
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If you can see the chromosomes they either are going to or just went through meiosis or mitosis. If you see Xs you know that it has not completely happened yet.
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What stages of meiosis and mitosis are the Xs pulled apart into one that looks like > and another that looks like <
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Anaphase of mitosis and Anaphase 2 of meiosis
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What phase of mitosis has the chromosomes lined up
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Metaphase
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What phase of mitosis has the chromosomes on the opposite sides of the cell
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Telophase
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Looking at a cell how do you know if it is in Telophase. Draw a cell in Telophase
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The chromosomes are 1 line not Xs and they are on opposite sides of a cell
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Looking at a cell how do you know if it is in Anaphase. Draw a cell in Anaphase
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Chromosomes are mostly in the middle but they are not Xs they were pulled apart
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Looking at a cell how do you know if it is in metaphase. Draw a cell in metaphase
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Chromosomes are mostly in the middle and they look like Xs
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Looking at a cell how do you know if it is in prophase. Draw a cell in prophase
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Xs are all clumped together in the same region not lined up
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Draw a cell right after cytokinesis
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Cell should have lines not Xs for their DNA and they should be inside a nucleus
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When does the nuclear membrane dissolve
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prophase
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Oversimplified point of Meiosis 1
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Pull double Xs apart in to individual Xs
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Oversimplified point of Meiosis 2
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Pull Xs apart into individual >
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What does a tetrad look like
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XX
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What is a chromosome?
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Tightly coiled strands of DNA and proteins (histones)
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Why are chromosomes only visible during certain times in the cell cycle?
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They are very condensed during mitosis, and unraveled during the rest of the cell cycle
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What is the cell cycle?
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A series of events that cells go through. It includes generally living growing and duplicating DNA and organelles (interphase) and splitting to become 2 new daughter cells (cell division - made of mitosis and cytokinesis)
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What are the phases of the cell cycle?
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Interphase is a period of growth and replication in between division
G1 phase: cell grows & makes proteins & organelles S phase: chromosome (DNA) replication (stands for synthesis) G2 phases: preparation for cell division (makes more molecules & organelle |
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What is the difference between mitosis and cytokinesis?
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1. Mitosis – division of the nucleus
2. Cytokinesis – division of the cytoplasm |
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Why is mitosis classified as asexual reproduction?
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Because the daughter cells are genetically identical to the parent
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What other purpose, besides reproduction, does mitosis serve?
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The source of new cells when an organism grows and develops
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What are the 4 phases of mitosis?
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Prophase, metaphase, anaphase, telophase
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How is cytokinesis in a plant cell different from cytokinesis in an animal cell?
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In a plant cell, a cell plate forms down the center of the cell. In an animal cell, a cleavage furrow is made by the cell membrane and the cell is pinched in two.
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What is cancer?
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Cancer is a disorder in which some of the body’s own cells lose the ability to control growth
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How are cancer cells different from normal cells?
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Caner cells do not respond to the signals that regulate the growth of most cells
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What is genetics?
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Genetics is the scientific study of heredity, inheritance passed down from one generation to the next
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Who is the father of genetics? What organism did he study?
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Gregor Mendel – pea plants
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What is fertilization?
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The process in which during sexual reproduction, male and female reproductive cells (gametes) join
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What are gametes?
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Sex, or reproductive, cells; sperm and egg
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What is self-pollinating?
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When one flower with both male and female reproductive organs pollinates itself to produce offspring
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What is true-breeding?
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A plant that if allowed to self-pollinate, would produce offspring identical to themselves
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What is cross-pollination?
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Joining male and female gametes from 2 different plants
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What is a trait?
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Specific characteristic that varies from one individual from another
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What 7 traits did Mendel study in pea plants?
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YOU SHOULD LOOK THIS UP AND INCLUDE IT IN THE FLASHCARD BY CLICKING EDIT
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What do the following letters stand for?P F1F2
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Parental Generation 1 Generation 2
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What is a hybrid?
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offspring of crosses between parents with different traits
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What is the Principle of Dominance?
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Some alleles are dominant and others are recessive
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What are genes?
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Genes – sequence of DNA that codes for a protein and thus determines a trait
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What are alleles?
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Alleles – different forms of a gene (e.g. tall or short)
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What is probability? What is the probability of a coin landing on heads
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The likelihood that a particular event will occur
50% |
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What is a Punnett Square used for?
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To predict the gene combinations that result from a genetic cross
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What do the letters in and around the Punnett Square represent?
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Alleles
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What is the difference between a capital letter and a lower case letter?
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Dominant & recessive
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What is a homozygous organism?
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Organisms that have two identical alleles for a particular trait
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What is a heterozygous organism?
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Organisms that have two different alleles for the same trait
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What is phenotype?
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Physical characteristics
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What is genotype?
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Genetic makeup
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Do Punnett Squares or other probability predictions always predict the exact outcome? Why?
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No, they are just predictions of what is likely to occur, not what will definitely occur.
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Explain the difference between a monohybrid cross and a dihybrid cross
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Dihybrid = 2-factor cross (e.g. seed color & seed shape)
Monohybrid = 1-factor cross (e.g. only seed color) |
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What is the predicted ratio of a completely heterozygous dihybrid cross?
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9:3:3:1
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What is the Principle of Independent Assortment?
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The principle of independent assortment states that genes for different traits can segregate independently during the formation of gametes
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incomplete dominance?
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Cases in which one allele is not completely dominant over another
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What is codominance?
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A situation in which both alleles contribute to the phenotype
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What is the exception of multiple alleles?
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A situation in which a gene has more than two alleles
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What are polygenic traits?
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Traits controlled by two or more genes
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Give an example of a trait controlled by multiple alleles.
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Blood type, rabbit coat color
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Give an example of a polygenic trait.
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Height, skin color
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What type of distribution do polygenic trait display?
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A normal, or bell, curve
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How many copies of chromosomes do gametes have? Why do gametes have this many?
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One, b/c the egg and sperm combine to produce an organism with 2 copies.
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What are homologous chromosomes?
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2 sets of chromosomes - have corresponding chromosomes from each parent
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Explain the difference between a diploid and a haploid cell.
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A cell that contains both sets of homologous chromosomes is called diploid
A cell that contains only 1 set of chromosomes |
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What types of cells are haploid? What types are diploid?
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Haploid – gametes
Diploid – all other body cells |
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What is meiosis?
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Meiosis is a process in which the number of chromosomes per cell is cut in half through the separation of homologous chromosomes in a diploid cell
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How many cells result from meiosis? Are they diploid or haploid
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4 - haploid
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Was the original parent cell of meiosis diploid or haploid?
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diploid
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What are the phases of meiosis?
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P I, M I, A I, T I and cytokinesis
P II, M II, A II, T II and cytokinesis |
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What is a tetrad?
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structure containing 4 chromatids that forms during prophase I of meiosis when each chromosome pairs with its corresponding homologous chromosome
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What is crossing-over?
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process in which homologous chromosomes exchange portions of their chromatids during meiosis, resulting in the exchange of genes, and therefore alleles, which produces new combinations of alleles
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What is there so many possibilities of how a child can come out from the same 2 parents
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Crossing over mixes up the DNA on homologous chromosomes (chromosomes with the same number)
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What is a chiasma?
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Site of crossing-over on chromosomes
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What is sperm?
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the haploid gametes produced by meiosis in males
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What are eggs?
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the haploid gametes produced by meiosis in females
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How does crossing-over create genetic variation?
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It mixes segments of chromosomes, and therefore genes, from both parents, so that the offspring have different combinations of alleles.
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Are the daughter cells of meiosis identical to the parent? Are they identical to each other? Why?
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No,No
Crossing-over led to genetic variation |
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How do the functions of mitosis and meiosis differ?
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Mitosis – asexual reproduction; replaces old and dead cells
Meiosis - mechanism in which sexually reproducing organisms produce gametes |
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If mom is heterozygous for a recessive sex linked disease what is the probability of her son getting the disease
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50%. The probability of getting the bad X chromosome is 50% and if the son gets it he will get the disease
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Explain independent assortment of chromosomes
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In metaphase I of meiosis the tetrads (double Xs) line up randomly so you might get dad's chromosome number 1 and mom's chromosome number 5 in the gamete
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Explain indpendent assortmnt of genes on a chromosome
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When chromatids that are crossed over are pulled apart sometimes they swap the parts that are crossed over. n
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