The Animal Cell

Obj 8.02

The Cell

• Body is made up of millions of cells• Basic unit of the body and life

Cell Parts

• Protoplasm– Material inside the cell

Cell Parts

• Cell Membrane– Thin layer of protein and fat that surround the cell– Allows and blocks certain substances from

entering

Cell Parts

• Centrosome– Small body where microtubules are made– Divide during mitosis

Cell Parts

• Nucleus– Gives the cell the ability to grow, digest food, divide– Contains DNA

Cell Parts

• Cytoplasm– Jelly like substance that gives the cell shape and

contain components necessary for cell functions

Cell Parts

• Golgi Body– Located near the nucleus and produces the

membrane that surrounds the lyosomes

Cell Parts

• Lyosome– Round shaped organelle that contains digestive

enzymes that allow digestion of cell nutrients

Cell Parts

• Mitochondrion– Rod shaped organelle that converts energy stored

in glucose into ATP (Adenosine TriPhosphate)

Cell Parts

• Nuclear Membrane– Surrounds the nucleus

Cell Parts

• Endoplasmic Reticulum– Transports materials through the cell– Rough ER has ribosomes and looks like layers– Smooth ER do not have ribosomes and looks like

small pipes

Cell Parts

• Vacuole– Fluid filled membrane that fills with food and

waste products inside the cell

Cell Parts

• Ribosome– Site of protein synthesis

Cell Division

• Mitosis– Results in animal growth– Animals begin as a single cell – Chromosomes duplicate as division occurs

Cell Division

• 4 stages of mitosis– Prophase: nucleolus disappears and centrioles

move to opposite ends of the cell. Fibers form and extend from centromeres

– Metaphase: fibers align the chromosomes along the middle of the nucleus

– Anaphase: paired chromosomes separate and move to opposite sides of the cell

– Telophase: nuclear membrane forms around the newly divided chromosomes and membrane contracts

Cell Division

• Meiosis– Produces the sex cells (gametes) to have ½ the

number of chromosomes that body cells have

Cell Division

• Gamete Formation– One set of chromosomes come from the sperm

and ovum– The zygote is created during fertilization and has

chromosomes from each parent. They match up based on genetic information

Cell Division

• Sex cell formation of the sperm and ova are also produced through meiosis– Production of sperm is called spermatogenesis• Males produce sperm at sexual maturity• Spermatocytes divide into spermatids

– Production of ovum is called oogenesis• Females produce ova at sexual maturity• Oocytes divide to form ovum. Ovum stores food for the

zygote (embryo)

Chromosomes

• Chromosomes are rod shaped bodies in pairs

– Cattle: 30 pairs– Hogs: 19 pairs– Chickens: 39 pairs– Humans: 23 pairs

Genes

• Genes control characteristics that are inherited from parents

• Dominant Genes hide the effect of recessive genes. Represented by a capital letter

• Recessive Genes are mask by dominant genes but show up when you cross breed

Genes

• Homozygous genes are the same on each allele

• Heterozygous genes that carry two different genes that will affect a trait

Heritability Estimates

• Heritability is the likelihood of a trait being passed down from parent to offspring

• The higher the heritability, the better the product

• Heritability estimates in cattle is higher than swine

• Used more for carcass quality than for reproduction