Cell membrane receives messages from other cells Separates

• 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 channel protein

carbohydrate chain cholesterol 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 Parent 1 2. Organisms inherit two copies of each gene, one from each parent. 3. The two copies separate during gamete formation (Meiosis). 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: m. RNA------ 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