Studied by 2 peopleWhat is an organelle?
organelles are specialized structures with specialized functions that perform various jobs inside cells.
form and function of a vacuole
Form: in a plant cell - looks like a liver, is large
in an animal cell - small
Function: store waste, nutrients and other substances. Plants have central vacuoles that store water.
form and function of a cell membrane
Form: outer wall/layer of a cell
Function: protect cell, is made of lipids to keep cell afloat
form and function of cytoplasm
Form: jelly like substance that fills the cell
Function: the medium for chemical reactions in the cell (ex, cell expansion, growth and replication). Contains nutrients.
form and function of nucleous
Form: a ball/circle
Function: brain of the cell, contains DNA/RNA, controls growth and reproduction
form and function of vesicles
Form: forms when part of the membrane pinches off.
Function: transports substances through the cell. Similar to vacuole.
form and function of the mitochondria
Form: oval like with substances inside
Function: converts chemical energy in sugar into usable energy
form and function of lysosomes
Form: tiny bubbles
Function: filled with enzymes that digest and break down bacteria and damaged cells
form and function of golgi apparatus
Function: Receives proteins from the endoplasmic reticulum. Modifies, sorts and prepares proteins for transport.
Form: a long wavy worm
form and function of Centrioles
Form: Hexagonal like tubes.
Function: made solely for mitosis/meiosis during interphase. Produce spindle fibres.
Form and function of Endoplasmic Reticulum
Form:
Rough E.R - wavy with dots
smooth E.R - coral
Function: Carry materials like proteins through the cell
Rough E.R - makes proteins
Smooth E.R - produces fats and oils
Form and function of ribosomes
Form: small little dots attached to rough E.R. or free in cytoplasm
Function: Where proteins are assembled
Form and function of cytoskeleton
Form: internal fibres made of protein filaments
Function: maintains cell shape
What are cilia/flagella
structures that provide the cell with movement, made of protein fibres.
flagella: long, few in numbers
cilia: short, numerous
Cell Wall
only in plant cells an bacteria cells
provides strength to the cell
Chloroplasts
only in plant cells
contains chlorophyll which is essential for photosynthesis
Compare a plant cell to an animal cell
Plant Cell:
have cell walls and chloroplasts
large central vacuole
contain chlorophyll
store energy in starches and oils
cell wall separates new cells after mitosis
Animal Cell:
specialized compounds in blood like hemoglobin
small vacuoles
store energy in fats and carbs
cleavage furrow that separates new cells in cytokinesis after mitosis
What is a prokaryotic cell?
Cells that do not contain membrane bound organelles. They are small and include bacteria, and archaea.
What is apoptosis?
Cell suicide. Happens as a defence mechanism caused by the immune system.
What is lumen?
the cavity within a tube like organ, examples: blood vessels, intestines.
What is a eukaryotic cell?
A cell with membrane-bound organelles, larger than prokaryotic cells. Include plants, animals, fungi and protists.
What does haploid mean?
a cell that has unpaired chromosomes. Sex cells/gametes are haploid.
What does diploid mean?
a cell containing two complete sets of chromosomes, one from each parent cell. Somatic cells (non-sex cells) are diploid.
Why does mitosis occur?
To grow new tissue and repair damaged tissue. When a cell grows too large to the point it can no longer function efficiently, it goes through mitosis and produces two identical daughter cells.
What is DNA?
Genetic information that is condensed and stored in chromosomes. Deoxyribonucleic Acid.
Explain the stages of the cell cycle/mitosis.
Interphase: 90% of the cell cycle.
G1 - Growth phase: where cells prep for replication.
Synthesis: replication of genetic info. 1 chromosome now has 2 sister chromatids.
G2 - final prep for mitosis. Where centrioles develop.
Prophase:
Nuclear membrane dissolves
Chromosomes condense
Centrioles move to opposite poles.
Metaphase:
Chromosomes line up at the mitotic plate
Spindle fibres develop and attach to the centromere of the chromosomes.
Anaphase:
Spindle fibres pull sister chromatids to opposite poles.
Telophase:
Chromosome lengthen
Spindle fibres break down
2 nuclei are formed surrounding the chromosomes at opposite ends.
Cytokinesis:
The 2 identical daughter cells are ripped apart either with a cleavage furrow (animal) or a cell wall (plant).
How is cancer linked to mitosis?
When there is abnormal cell division (is sporadic and occurs too often) it causes tumors to form. They can either be benign, or malignant and spread throughout the body.
What is a centromere?
The spot where two sister chromatids are attached. Where the spindle fibres pull.
What is a homologous pair?
One chromosome from the mom and one from the dad that code for the same genetic trait. One of the pair is called a homologue. There are variations in traits (ex; dad codes blonde hair mom codes brown).
Explain the differences between a chromatin, and chromosome and a chromatid.
Chromatin: thread-like structure made up of DNA and proteins in the nucleus of a eukaryotic cell
Chromosome: structure in the nucleus of a eukaryotic cell that carries genes, formed when chromatin condenses
Chromatid____: each of the two identical chromosome strands in a replicated chromosome attached by their shared centromere
How any homologous pairs does the human body have?
23 homologous pairs of chromosomes (46 total) that are diploids or 2n.
What does meiosis produce? What is the end product?
Gametes: reproductive cells (ova or sperm). Gonads are the part of the body that produce gametes (ovaries and testicles). Two different divisions and four gametes are produced. Each gamete contains different genetic info.
What criteria must be present for meiosis to occur?
The organism must be a sexually reproducing, eukaryote, with at least diploid cells.
Meiosis 1
Pre-meiotic Interphase: Happens before meiosis 1. DNA replicates and sister chromatids attach at the centromere.
Prophase 1:
Synapsis: where homologous chromosomes pair up.
Crossing Over: For genetic variability.
Maternal and paternal chromatids exchange genetic information by crossing over at a random spot called the chiasmata.
The four chromatids are now called a tetrad and are attached with a kinetochore.
Centrioles move to opposite ends and spindle fibres appear.
Nuclear membrane dissolves
Metaphase 1:
tetrads line up at the mitotic plate (independent assortment)
spindle fibres attach to kinetochore
Anaphase 1:
Chromosomes are pulled apart by spindle fibres
sister chromatids are still intact, cells are haploid
Telophase 1:
Nuclear membrane reforms
Spindle fibres disintegrate
Cytokinesis 1:
Cytoplasm divides in half, creating two genetically variable haploid daughter cells
Meiosis 2
NO interphase or replication of DNA
Prophase 2:
Chromosomes condense
Centrioles move to opposite poles
Spindle fibres appear
Metaphase 2:
Chromosomes line up at the mitotic plate
Spindle fibres attach to the centromere
Anaphase 2:
Chromosomes are pulled apart and moved to opposite poles
Telophase 2:
Chromosomes unwind
Nuclear envelop reforms
Cytokinesis 2:
Produces 4 haploid gamete cells
3 polar bodies and 1 egg
4 sperm cells
All cells are genetically variable
What is a nucleic acid?
Long polymers that hold information that specifies the structures of proteins made in a cell. Determine the function of a cell and are essential for growth and development of all organisms.
What is the structure of a nucleic acid?
Subunits that are called nucleotides
3 parts to a nucleotide
Pentose sugar
Phosphate group
Nitrogen Base
What are the types of nitrogenous bases?
2 types
Purines: Adenine and Guanine
Large double ringed compounds
Pyrimidines: Cytosine Thymine, Uracil (RNA)
Smaller, single ringed
How are the nitrogenous bases paired.
DNA:
A + T
C + G
RNA:
A + U
C + G
What are the types of nucleic acids?
Both store heredity information
DNA:
deoxyribonucleic acid
found in the nucleus and is the main component of genes
Sugar in nucleotide is called deoxyribose sugar
double helix chain
RNA:
Contains protein-making instructions
Ribose sugar
What is Heredity?
Process of genetic traits being passed down from the parent to the the child.
What is a locus?
The location of a gene on a chromosome.
What is gametogenesis?
Gamete formation after meiosis.
Oogenesis?
Egg formation.
diploid oogonia
primary oocytes
1 egg + 3 polar bodies
Spermatogenesis?
Sperm formation
diploid spermatogonia
primary spermatocytes
4 spermatids (haploid)
What is nondisjunction?
Mistakes in meiosis that cause abnormal zygote formation: aneuploidy.
When homologous pairs don’t split properly or sister chromatids don’t separate.
What is monosomy?
Fertilized cell is missing a chromosome (45)
What is trisomy?
Fertilized cell has an extra copy of a chromosome (47)
What do nondisjunction disorders cause?
Results in cells not being able to function properly - genetic disorders.
How can nondisjunction be identified?
Karyotyping!!!!!! Recommended for women over 35, can be done through processes like amniocentesis.
What are the different types of abnormal chromosome structure?
Deletion: chromosome fragments fail to attach properly after crossing over
Duplication: chromosome fragment reattaches to an already complete homologue
Inversion: Attaches to the correct homologue in the wrong order
Translocation: Chromosome fragment attaches to a non homologous chromosome
Who is Gregor Mendel?
Father of modern genetics ;)!!!!! Conducted experiments on pea plants to understand inheritance.
What happened in the F1 and F2 generations of Mendel’s experiment?
Crossed white (recessive) and purple (dominant) flowering pea plants.
F1 gen: all purple
F2 gen: 3:1 ratio, purple:white flowers
Why did Mendel choose pea plants?
Because they are self-fertilizing (have male and female parts), reproduce quickly, and are true breeding (exhibit the same traits gen after gen).
What is Mendel’s first law?
When true breeding organisms with contrasting form of a trait are crosse, offspring with express only one form of the trait.
What is the law of segregation?
Factors segregate randomly during gametogenesis. An organism can only pass on one of its two genes.
What is the law of dominance?
Dominant alleles masc recessive alleles.
What is the law of independent assortment?
genes found in separate chromosomes are inherited independently of each other.
Homozygous
Has two of the same allele (HH or hh)
Heterozygous
Has two different alleles (Hh)
Genotype
Genetic makeup of alleles (HH, Hh, or hh)
Phenotype
Appearance of the expressed trait/allele (purple or white flowers)
Monohybrid Cross
Used to calculate the probability of inheriting a specific trait.
Test Cross
Determines the genotype of an individual by crossing it with a homozygous recessive.
What are non-mendelian genetics
Instances where complete dominance did not apply
What is complete dominance?
When the dominant allele fully masks the recessive allele (pea plants). (hahhahah pea pee ahah)
What is incomplete dominance?
When the different alleles of a gene produce and intermediate phenotype.
when one allele is not completely dominant
C^R (red flower) and C^W (white flower) make C^RC^W (pink flowers)
What is co-dominance?
When two alleles are expressed at the same time
Parent 1 = RR (red fur)
Parent 2 = WW (white fur)
Child = RW (roan fur)
How does co-dominance apply to blood types?
AB blood type is co dominant (I^AI^B). AB is a universal recipient while O is a universal donor.
What is a dihybrid cross?
Determines the genotypic and phenotypic combos for two unlinked genes (law of assortment).
What are the steps of a dihybrid cross?
Determine genotype of each parent
FOIL (determine gamete combos)
Draw 4x4 punnet square
PUNNET!!!!!!!
What is gene linkage?
When genes on the same chromosome are inherited together.
How many genes do human have?
between 27 000 - 40 000
What are x linked genes/traits?
Traits that are only on the x chromosome. The x chromosomes is always expressed in males.
red-green colourblindness and hemophilia are examples of x-linked traits.
Advantages of asexual repoduction
no need for mate
no mutations
Advantages of sexual reproduction
genetic variability
What is is genetically modified organism?
Organisms that have been bred in ways that would not occur naturally. Bt corn.
What is a restriction enzyme?
It can cut genetic material allowing it to be paired up with something else. Restriction enzymes leave sticky ends on the material they cut, if two things have been cut by the same enzyme their sticky ends can match up.
How are artificial insemination and invitro fertilization different?
Invitro inserts an already fertilized embryo where artificial insemination only inserts the sperm.
Why are the chances of a couple having a child with down syndrome much higher if the mother is over 35?
The gamete cells becomes weaker with age. They become more prone to nondisjunction.
Note
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