Animal Physiology and Understanding Animal Reproduction

1. Animal Physiology and Understanding Animal Reproduction Essential Standard 8.00 Understand animal reproduction Objective 8.02 Understand genetics of animal breeding.

2. Animal Cell • The body is made up of millions of tiny structural units called cells! • The cell is the basic unit of the body that supports and sustains life of an animal.

3. Nucleus Cytoplasm Cell Membrane Animal Cell

4. Cell Parts • Protoplasm • The material or contents inside of a cell • Cell Membrane • A thin layer of protein and fat that surround the cell • Some substances can pass into the cell • The membrane blocks other materials from entering • Centrosome • Small body where the microtubules are made • The centrosome divides during mitosis

5. Cell Parts • Nucleus • Gives cell ability to grow, digest good, and divide • Contains chromosomes and DNA • Cytoplasm • A jellylike substance that gives the cell shape and contains components necessary for cell functions • Golgi Body • Located near the nucleus and produces the membrane that surrounds the lysosomes.

6. Cell Parts • Lysosome • Round shaped organelles that contain digestive enzymes that allow for digestion of cell nutrients • Mitochondrion • Rod-shaped organelles that contain digestive enzymes that allow for digestion of cell nutrients • Nuclear Membrane • The membrane that surrounds the nucleus

7. Cell Parts • Nucleolus • Organelle found inside the nucleus • Produced ribosomal RNA • Endoplasmic Reticulum • Transports materials through the cell • Vacuole • Fluid filled membrane that fills with food and waste products inside the cell • Ribosomes • Site of protein synthesis

10. Cell Division

11. Mitosis • Type of cell division that increases the total number of cells and results in animal growth with the chromosome pairs being duplicated in each new cell • Results in animal growth • Animals begin as a single cell • Chromosomes are duplicated in each new cell as division occurs

12. Mitosis Steps • Prophase • The nucleolus disappears and centrioles move to opposite end of the cell • Fibers begin to form and extend the centromeres • Metaphase • Spindle fibers align the chromosomes along the middle of the cell nucleus • Anaphase • The paired chrosomes separate and move to opposite sides of the cell • Telophase • Nuclear membrane forms around the newly dividied chromosomes and cell membrane begins to contract

16. Mitosis Video Mitosis Video

17. Meiosis Type of cell division that produces the sex cells or gametes that have ½ the number of chromosomes that body cells have

18. Gamete Formation • One set of chromosomes come from the sperm and one from the ovum • The zygote that is created during fertilization has chromosomes from each parent • Chromosomes match up with one another based on the genetic information they carry.

19. Sex Cell Formation • Sex cell formation of the sperm and ova are also produced through meiosis • Production of sperm is called spermatogenesis • Male animals begin producing sperm at sexual maturity • Spermatocytes divide into spermatids through meiosis • Production of ovum is called oogenesis • Females also begin producing ova at sexual maturity • The oocytes divide and form an ovum • The ovum contains cytoplasm and stored food. • It provides nourishment for the zygote and embryo.

21. Meiosis Video Meiosis Video

23. Chromosomes • Rod shaped bodies • Made of protein • Found in the cell nucleus • Exist in pairs except for gamete cells • The number of chromosome pairs differ for various animals • Cattle 30 • Swine 19 • Horses 33 • Chickens 39 • Humans 23

24. Genes • Located on chromosomes • Thousands found in each animal • Control inherited characteristics from parents • Carcass traits • Growth rate • Feed efficiency • Two types of inherited traits • Dominant • Recessive

25. Two Types of Genes • Dominant • Hides the effect of recessive genes (covers recessive traits) • Represented by a capital letter • Recessive • Masked by dominant genes (can show up in heterozygous gene pairs) • Pp x Pp combine as homozygous recessive “pp” • In this case, if “p” is the recessive trait for horns, the calf will have horns.

26. Homozygous and Heterozygous • Homozygous gene pair • Carries two genes for a trait • Polled cow might carry the gene PP • Heterozygous • Carries two different genes that affect a trait • Polled cows might carry a recessive gene with the dominant Pp

27. Heritability Estimates

28. Heritability • Estimated the likelihood of a trait being passed on from the parent to the offspring • Heritability estimates vary from 0% to about 70% • If a trait is highly heritable, a producer will see improvements faster than traits that have a low heritability estimate • Heritability estimates for traits in beef cattle are generally higher than for traits in swine.

29. Heritability • Heritability traits are usually higher for carcass quality traits than for reproduction traits in both swine and cattle. • Traits with low heritability estimates are improved most through environment. • Those traits with high heritability estimates are improved most by selective breeding and environmental improvements.

30. Questions?

31. Web Resources Parts of the Cell Inside the Cell Video