What is a composite cell?
A typical cell diagram that includes characteristics of many cells
Why do we use composite cells?
To give us a generalized sketch of a cell with typical characteristics
How many cells are in an average adult human body?
37 trillion+
Do all cells look alike? What determines the structure of a cell?
NO. The function determines the structure of a cell
What is interstitial fluid?
Diluted saltwater solution that is derived from blood that bathes the cells in our body
What are the primary functions of a cells nucleus?
It's the site of DNA replication, controls cell reproduction, and it contains DNA/genes
What occurs in the nucleolus (or nucleoli?)
Ribosomes are produced
What are the primary functions of the cell membrane? Determines what..
enters and leaves the cell
Describe the cell membrane
Fragile, transparent, many folds, bi-layered
Why is the membrane called "selectively permeable
Some things can get through, others cannot
What is a desmosome?
Structures that hold cells together using filaments. ex: skin cells
Describe cytoplasm
Cellular material outside of the nucleus, but inside the membrane
3 parts of cytoplasm
cytosol, organelles, and inclusions
Cytosol
Fluid with nutrients and salts
inclusions
nutrients; may or may not be present in cytoplasm
Mitochondria
breaks down food to release energy (heat & ATP)
Golgi Apparatus
modifies and packages proteins
Ribosomes
site of protein synthesis
Smooth and Rough Endoplasmic Reticulum
passageways for transport of substances
Lysosomes
has enzymes that help rid of wastes, worn out cell parts, and bacteria
Peroxisomes
contains oxidase enzymes that neutralize poisons such as alcohol and formaldehyde
How many different types of cells are there in the human body?
200
What is cell differentiation?
Process by which cells develop specific structures and functions
Fibroblast
secretes filaments for connecting tissues
Erythrocytes
red blood cells, carry oxygen
Epithelial
hexagon shaped, resists tearing, tightly packed
Adipose
FAT, few organelles
Neuron
long process for sending/receiving messages
Ovum
many organelles (egg)
Sperm
stream lined for swimming. takes 175,000 sperm to equal the weight of one egg
Macrophage
has many lysosomes and a pseudopod (fake legs) to crawl
What is active transport
used ATP/energy to move substances
What is passive transport?
used no energy to move substances
What does extra cellular mean?
outside the cell
What does intercellular mean
inside the cell
What does intracellular mean?
between the cells
What is exocytosis?
materials are released from cell
What is endocytosis?
Materials are taken into the cell
pincocytosis:
cell drinking (liquids)
Phagocytosis:
cell eating (solids)
The two main parts of cell division are
mitosis and cytokinesis
Sex cells undergo what?
meiosis
Why do sex cells go through meiosis in place of mitosis?
Sex cells must have 1/2 the number of chromosomes