Transcript 1 2 - Cloudfront.net

•Cell membrane: receives messages from other cells
•Separates interior material from outside environment
•Selectively permeable (only certain things can move in an out)
• A phospholipid is a molecule composed of
three basic parts:
• A charged phosphate group
• Glycerol
• two fatty acid chains
Head
• The head is polar
• interacts with water
• Hydrophilic
• Attracted to water
• The tail is non-polar
• repelled by water
• hydrophobic
• Attracted to other tails
Tail
*Phospholipids arrange themselves like a sandwich into two
layers.
Contain:
•Proteins
•Cholesterol
•Carbohydrates
cell membrane
carbohydrate
chain
cholesterol
protein
protein channel
protein
carbohydrate
chain
cholesterol
protein
protein channel
protein
– The cell membrane is selectively permeable.
*Draw a
picture on the
bottom of pg.
30
Some molecules can cross the
membrane while others cannot.
Homologous Chromosomes
• Homologous chromosomes
are very similar to one another
• Carry the same genes
• One from Mom
• One from Dad
Crossing over during meiosis increases
genetic diversity.
• Crossing over is the exchange of chromosome
segments between homologous
chromosomes.
– occurs during prophase I of meiosis I
– results in new combinations of genes
• Meiosis has 2 cell divisions
• Results in 4 unique haploid
cells
1
2
6.1 Chromosomes and Meiosis
• You have two types of specialized cells:
Somatic cells
and
Germ cells
Will become…
6.1 Chromosomes and Meiosis
Germ cells- are the cells in your
reproductive organs
•located in the ovaries and testes
•Develop into gametes
6.1 Chromosomes and Meiosis
Gametes are sex cells: egg and sperm
•Both have DNA that can be passed to offspring.
Egg
Sperm
6.1 Chromosomes and Meiosis
• Gametes are Haploid (n) cells have one copy of every
chromosome.
–Have 22 autosomes + 1 sex chromosome = 23
chromosomes each
23
23
6.1 Chromosomes and Meiosis
• You have two types of specialized cells:
Somatic cells
Germ cells
• Undergo mitosis
• Undergo meiosis
• body cells
• Cells in reproductive
organs
(ovaries/testies)
• Diploid
• 46 chromosomes
• Become gametes
(sperm/eggs)
• Identical to parent
cell
• Haploid
• 23 chromosomes
• Each are Unique
6.1 Chromosomes and Meiosis
• You have two types of chromosomes:
Autosomes
and Sex Chromosomes
6.1 Chromosomes and Meiosis
•Chromosome
pairs 1-22 are
called autosomes
•Contain genes
not directly
related to your
gender
6.1 Chromosomes and Meiosis
Pair #23=Sex chromosomes: X and Y
•determine gender
•Control the development of sexual
characteristics
XX= female
XY= male
XX
XY
6.3 Mendel and Heredity
• Mendel observed patterns in the first and second
generations of his crosses.
6.3 Mendel and Heredity
• Mendel drew three important conclusions from his
observations and experiments with pea plants
1. Traits are inherited as discrete units/
individually. (genes)
LAW OF SEGREGATION
purple
2. Organisms inherit two copies of each
gene, one from each parent.
3. The two copies separate
during gamete formation (Meiosis).
Parent
1
white
Parent
2
• Experiments with dihybrid
crosses (2 traits) led to
Mendel’s second law, the law
of independent assortment.
• The law of independent
assortment states that allele
pairs separate
independently of each other
during meiosis.
Ex:
Hair color is inherited separately from
eye color
Pea color is inherited separately from
pea shape
Hair line inherited separately from
earlobes
8.2 Structure of DNA
Please draw and label a strand of DNA:
1. Phosphate
2. Deoxyribose sugar
3. Nitrogen bases:
Adenine
Guanine
Cytosine
Thymine
4. Backbone
Pg. 62 in INB
Pg. 230-233 in book
hydrogen bond covalent bond
Please answer the following genetics questions
using a punnett square:
1. Let's say that in seals, the gene for the length of the whiskers has two
alleles. The dominant allele (W) codes long whiskers & the recessive allele (w)
codes for short whiskers.
a) What percentage of offspring would be expected to have short whiskers
from the cross of two long-whiskered seals, one that is homozygous dominant
and one that is heterozygous? Genotype? Phenotype?
b) If one parent seal is pure long-whiskered and the other is short-whiskered,
what percent of offspring would have short whiskers? Genotype?
Phenotype?
2. A green-leafed luboplant is crossed with a luboplant with yellow-striped
leaves. The cross produces 185 green-leafed luboplants. Summarize the
genotypes & phenotypes of the offspring that would be produced by crossing
two of the green-leafed luboplants obtained from the initial parent plants.
3. In purple people eaters, one-horn is dominant and no horns is recessive.
Draw a Punnet Square showing the cross of a purple people eater that is hybrid
for horns with a purple people eater that does not have horns. Summarize the
genotypes & phenotypes of the possible offspring.
Please complete the translation/transcription
comparison of primates:
Transcription: DNA-----------RNA
(ATCG)
(AUCG)
Practice: DNA: GAG AAA GTA CGT AGT CCA
RNA: CUC UUU CAU GCA UCA GGU
Translation: mRNA-----------Proteins
(AUCG)
(polypeptide chain- amino acids)
Practice: RNA: CUC UUU CAU GCA UCA GGU
Amino Acid: Leu Phe His Arg Leu Gly
Chart on Pg. 244 in book